Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses: Variability According to Phototypes 3031196872, 9783031196874

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Enzo Errichetti Richard P. Usatine Balachandra S. Ankad Aimilios Lallas Editors

Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses Variability According to Phototypes

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Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses

Enzo Errichetti  •  Richard P. Usatine Balachandra S. Ankad  •  Aimilios Lallas Editors

Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses Variability According to Phototypes

Editors Enzo Errichetti Department of Medical Area University of Udine, Institute of Dermatology Udine, Italy

Richard P. Usatine Dermatology and Cutaneous Surgery University of Texas Health, San Antonio San Antonio, TX, USA

Balachandra S. Ankad Department of Dermatology S Nijalingappa Medical College Bagalkot, Karnataka, India

Aimilios Lallas First Department of Dermatology Aristotle University of Thessaloniki Thessaloniki, Thessaloniki, Greece

ISBN 978-3-031-19687-4    ISBN 978-3-031-19688-1 (eBook) https://doi.org/10.1007/978-3-031-19688-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

To my wife Sabrina and my children Mattia and Martina, the greatest joys of my life. To my parents Mario and Carmen, thanks for being so proud of me. To my patients, without whom I would not have achieved my professional aims. Enzo To my wife Janna and my children Rebecca and Jeremy. Thanks for your love and support over many years. To Dr. Ash Marghoob my original mentor in dermoscopy. Thanks for your ongoing support and friendship in improving the care of our patients with the science of dermoscopy. Much thanks to my international coauthors. What a pleasure it has been to collaborate on this work. Richard To my parents and my wife Roopa and my children Tanush and Srijani for always being supportive and bringing joyous moments in my life. To my mentor Dr. Arun Inamadar who is an inspiration in academic endeavors. To all my patients who teach me a lot of dermatology and dermoscopy every single day. Balachandra To my wonderful group of collaborators with whom I work daily. Aimilios

Preface

Dermatology is one of the most challenging branches of medicine where the diagnosis mostly relies on the morphology of the lesions, similarly to radiology and pathology. However, unlike these disciplines, a dermatologist may come across different color backgrounds that may completely change the meaning of what we have in front, so the examinator needs to know any point of difference of physical assessment according to the phototype. In this book, we address the presentations of the main non-neoplastic dermatoses but also less common conditions in light and dark skin, pointing out any possible variations from both clinical and dermoscopic point of view as only their combination may enhance diagnostic accuracy. The need for such a book is even greater in a cosmopolitan society where dermatologists encounter patients with various phototypes. To achieve our aim, we asked the help of esteemed international researchers in the field of dermoscopy of non-neoplastic dermatoses and put together a puzzle of information illustrated by over 900 images, also including still unpublished details. We hope that this book will facilitate your practice regardless of the skin tone you are examining. Have a nice reading! Udine, Italy San Antonio, TX, USA  Bagalkot, Karnataka, India  Thessaloniki, Thessaloniki, Greece 

Enzo Errichetti Richard P. Usatine Balachandra S. Ankad Aimilios Lallas

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Contents

1 Introduction�����������������������������������������������������������������������������������������������������������������   1 Enzo Errichetti, Richard P. Usatine, Balachandra S. Ankad, and Aimilios Lallas Part I Inflammatory Diseases 2 Common Papulosquamous Disorders�����������������������������������������������������������������������   7 Enzo Errichetti 3 Less  Common Papulosquamous Disorders �������������������������������������������������������������  27 Enzo Errichetti, Nkechi A. Enechukwu, and Payal Chauhan 4 Other Papulonodular Disorders �������������������������������������������������������������������������������  45 Enzo Errichetti 5 Noninfectious Granulomatous Disorders�����������������������������������������������������������������  57 Enzo Errichetti 6 Connective Tissue Diseases�����������������������������������������������������������������������������������������  67 Enzo Errichetti, Balachandra S. Ankad, Biswanath Behera, and Aimilios Lallas 7 Facial Inflammatory Dermatoses �����������������������������������������������������������������������������  87 Balachandra S. Ankad, Shishira Jartarkar, Ibrahima Traoré, Biswanath Behera, and Enzo Errichetti 8 Common Hyperpigmented Dermatoses�������������������������������������������������������������������  97 Shekhar Neema, Balachandra S. Ankad, and Enzo Errichetti 9 Less  Common Hyperpigmented Dermatoses����������������������������������������������������������� 111 Shekhar Neema and Enzo Errichetti 10 Common Hypopigmented Dermatoses��������������������������������������������������������������������� 125 Balachandra S. Ankad, Sankappanavara V. Smitha, and Enzo Errichetti 11 Less  Common Hypopigmented Disorders ��������������������������������������������������������������� 137 Balachandra S. Ankad, Shibani Bhatia, and Enzo Errichetti 12 Infiltrative Dermatoses����������������������������������������������������������������������������������������������� 145 Enzo Errichetti, Balachandra S. Ankad, Soumil Khare, Biswanath Behera, and Payal Chauhan 13 Miscellaneous��������������������������������������������������������������������������������������������������������������� 163 Balachandra S. Ankad, Sushila Nagur, Biswanath Behera, and Enzo Errichetti

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Part II Infectious Diseases 14 Bacterial Infections����������������������������������������������������������������������������������������������������� 175 Balachandra S. Ankad, Varsha R. Koti, Payal Chauhan, Matilde Krisha P. Montenegro, Katherine Joy Sayo-­Aguiling, and Enzo Errichetti 15 Parasitoses������������������������������������������������������������������������������������������������������������������� 195 Richard P. Usatine, Tizita Yosef, Maria LaPlante, Balachandra S. Ankad, Elizabeth Leocadia Fernandes, and Enzo Errichetti 16 Mycoses ����������������������������������������������������������������������������������������������������������������������� 209 Richard P. Usatine, Balachandra S. Ankad, Nkechi A. Enechukwu, Tizita Yosef, Elizabeth Leocadia Fernandes, and Enzo Errichetti 17 Viral Infections����������������������������������������������������������������������������������������������������������� 223 Richard P. Usatine, Aimilios Lallas, and Enzo Errichetti Part III Hair and Nail Diseases 18 Nonscarring Alopecias ����������������������������������������������������������������������������������������������� 235 Adriana Rakowska, Richard P. Usatine, Tiffany T. Mayo, Nkechi A. Enechukwu, and Enzo Errichetti 19 Scarring Alopecias ����������������������������������������������������������������������������������������������������� 253 Adriana Rakowska, Richard P. Usatine, Maria LaPlante, Adriana Arocha, Leah Shama, Sujitha Yadlapati, Tiffany T. Mayo, Nkechi A. Enechukwu, and Enzo Errichetti 20 Inflammatory Nail Conditions����������������������������������������������������������������������������������� 267 Michela Starace, Tanuja Rajagopal, and Balachandra S. Ankad 21 Onychomycosis  and Other Nail Infections��������������������������������������������������������������� 279 Michela Starace, Balachandra S. Ankad, and Anusha H. Lokesh 22 Traumatic Nail Disorders������������������������������������������������������������������������������������������� 289 Michela Starace, Balachandra S. Ankad, and Akash Gupta

Contents

1

Introduction Enzo Errichetti, Richard P. Usatine, Balachandra S. Ankad, and Aimilios Lallas

Contents References

Diagnosis in dermatology is a complex puzzle in which physical examination plays a primary role, especially when it comes to non-neoplastic dermatoses [1, 2]. Indeed, analysis of localization, distribution, and morphological details (color, surface, shape, margins, etc.) of the lesions may allow the clinician to either make a specific diagnosis or narrow the differential diagnosis to a limited number of conditions [1, 2]. Of note, while in the past physical examination was intended only as clinical assessment, over the last few years dermoscopic analysis has become an important complement for the evaluation of the patients [3, 4]. Importantly, skin phototype may significantly affect presentation of many dermatoses, from both clinical and dermoscopic points of view [1, 2, 5]. In general, such differences are due to the diverse background of color and specific reaction patterns that are encountered more commonly in dark phototypes (IV–VI), such as lability of pigment and greater tendency for follicular or sclerotic reactions [5]. One of the most important differences on clinical examination is the shade of erythema that appears red in fair skin

E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy R. P. Usatine Dermatology and Cutaneous Surgery, University of Texas Health, San Antonio, San Antonio, TX, USA B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India A. Lallas First Department of Dermatology, Aristotle University of Thessaloniki, Thessaloniki, Thessaloniki, Greece

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and brownish in skin of color, thus being difficult to be detected in very dark-skinned patients [2]. So, in this scenario, comparison with surrounding healthy skin may be of aid to appreciate erythematous skin [2]. Notably, as a consequence of the above-mentioned reaction patterns, scarring and pigmentary dermatoses in skin of color may show a more marked fibrosis/pigmentation, respectively [2]. Accordingly, inflammation-induced pigmentation is seen more frequently in dark-skinned patients; thereby some dermatoses may feature a brown shade that is usually not seen in lighter phototypes [2]. Moreover, due to the higher tendency to both papular and follicular reactions in skin of color, some conditions may display papular or follicular presentations (e.g., papular/follicular eczema, follicular psoriasis, and papular pityriasis rosea), which are more uncommon in fair skin [2]. Finally, due to the greater contrast, hypopigmented dermatoses are typically more noticeable in skin of color, even in initial phases/subtle cases, that are difficult to detect in fair-skinned patients [2]. Of note, besides the aforementioned general differences, many other clinical points of variation according to the phototype do exist in specific diseases, which are addressed in detail throughout the book. Moving to dermoscopic examination (Fig. 1.1), the physiological presence of a brown network-like pigmentation in skin of color may make vascular structures less visible, similarly to what happens with subtle pigmentary changes [2, 5]. Conversely, depigmentation or white areas are more noticeable in dark phototypes due to the greater optical contrast [2, 5]. Additionally, the brown background may modify the shade of some relevant structures. For instance, granulomatous infiltration of the dermis usually gives rise to a typical orange hue in fair skin, while it looks yellowish in skin of color [2, 5]. Another example is ashy dermatosis, which

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_1

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b

Fig. 1.1  Normal skin in fair- (a) and dark-skinned (b) patients on dermoscopy; an intense pigmented network is evident in skin of color that may obscure other dermoscopic findings, especially vessels (b)

a

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Fig. 1.2  Normal scalp in fair- (a) and dark-skinned (b) patients on dermoscopy; regularly distributed eccrine openings appearing as white dots (b)

f­ eatures light blue dots in light phototypes, yet pigmentation may be so intense in very dark-skinned patients that dots may appear dark blue to black [2, 5]. Importantly, the evidence of acrosyringeal and follicular openings on dark scalp (seen as pinpoint white dots in the context of the physiological pseudonetwork—Fig. 1.2) often makes distinguishing non-scarring from scarring alopecia easier based on the distribution of pinpoint white dots, which is regular and irregular, respectively (Fig. 1.3) [2]. Additionally, irregular fibrotic white patches may also be visible between the white dots in scarring alopecia (Fig. 1.3) [2]. However, in scarring alopecias with sparing of the interfollicular areas (e.g., lichen planopilaris or other folliculocentric alopecias), the presence of preserved multiple pinpoint dots may make absence of follicular openings less apparent, especially in early/subtle

instances [2]. Moreover, due to the pigmented background, some faint follicular changes may be less evident in dark scalp (e.g., yellow dots), while white fibrotic changes (appearing as bright white areas) are typically more noticeable [2]. Of note, since lability of pigment and follicular/ sclerotic reactions are more frequent in skin of color, it is more common to appreciate pigmentary/white fibrotic structures that may cover other findings, such as vessels [2, 5]. Finally, the higher prevalence of changes involving adnexal structures in dark phototypes lead the International Dermoscopy Society to add further “adnexal” variables in the list of the basic parameters to assess in non-neoplastic dermatoses for skin of color, including perifollicular scales, follicular openings obliteration, broken hairs, eccrine pigmentation, and eccrine ostia obliteration (Fig. 1.4) [6].

1 Introduction

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Fig. 1.3  Dermoscopy of non-scarring (alopecia areata) (a) vs. scarring (discoid lupus erythematosus) (b) alopecia in dark-skinned patients displaying regularly and irregularly distributed white dots (eccrine openings), respectively; irregular fibrotic areas are also evident in the latter (b)

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Fig. 1.4  Examples of “adnexal” dermoscopic variables considered to be relevant in skin of color, including perifollicular scales and broken hairs (arrow) (a), follicular openings obliteration (arrow) (b), eccrine pigmentation (c), and eccrine ostia obliteration (arrow) (d)

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References 1. Lallas A, Errichetti E, Ioannides D. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. 2. Errichetti E, Lallas A. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. 3. Errichetti E, Stinco G. Dermoscopy in general dermatology: a practical overview. Dermatol Ther (Heidelb). 2016;6:471–507. 4. Errichetti E.  Dermoscopy of inflammatory dermatoses (inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80.

E. Errichetti et al. 5. Errichetti E, Ankad BS, Sonthalia S, et  al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the International Dermoscopy Society. Eur J Dermatol. 2020;30:688–98. 6. Errichetti E, Ankad BS, Jha AK, et  al. International Dermoscopy Society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71.

Part I Inflammatory Diseases

2

Common Papulosquamous Disorders Enzo Errichetti

Contents 2.1 2.1.1  2.1.2  2.1.3 

Psoriasis  Introduction  Clinical Presentation  Dermoscopy 

 7  7  8  10

2.2 2.2.1  2.2.2  2.2.3 

Dermatitis  Introduction  Clinical Presentation  Dermoscopy 

 12  12  12  12

2.3 2.3.1  2.3.2  2.3.3 

Lichen Planus  Introduction  Clinical Presentation  Dermoscopy 

 17  17  17  19

2.4 2.4.1  2.4.2  2.4.3 

Pityriasis Rosea  Introduction  Clinical Presentation  Dermoscopy 

 20  20  20  21

2.5 2.5.1  2.5.2  2.5.3 

 ichen Simplex Chronicus and Lichenification  L Introduction  Clinical Presentation  Dermoscopy 

 22  22  23  23

2.6 2.6.1  2.6.2  2.6.3 

 rictional Lichenoid Dermatitis  F Introduction  Clinical Presentation  Dermoscopy 

 24  24  25  25

References 

2.1 Psoriasis 2.1.1 Introduction Psoriasis is a chronic inflammatory condition mainly affecting the skin, nail, and joints which displays a strong genetic predisposition and autoimmune pathogenic traits [1–3]. It

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presents two peaks of onset (20–30 and 50–60 years of age), yet it may manifest at any age [1–3]. The worldwide prevalence is about 2%, but it remarkably varies according to geographic areas/ethnicity, with a lower prevalence in dark-skinned populations compared to Caucasian subjects, which may show figures up to 11% (Scandinavian populations) [1–3].

E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_2

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2.1.2 Clinical Presentation Plaque-type psoriasis, also known as psoriasis vulgaris, is the most frequent clinical variant [1–3]. It presents with either asymptomatic or itchy, well-demarcated plaques typified by a white/silvery scaling (Figs.  2.1a, 2.2, 2.3, 2.4a) most commonly involving the scalp, elbows, knees, genitalia, sacral area, and palmoplantar surface, though any body area may be involved [2, 3]. Lesions in fair skin tend to display an ery-

a

thematous background (Figs. 2.1a and 2.3a), which is usually absent in darker phototypes [2, 3]. In fact, in such patients, the plaques feature a brown or violaceous hue (Figs.  2.2a and 2.4a), albeit hyperkeratosis is sometimes so pronounced that the lesions appear gray (Fig. 2.4a) [2, 3]. Another remarkable difference compared to lighter skin is the common occurrence of post-inflammatory dyspigmentations (hyper- or hypo-pigmentations), which is even more evident in very dark phototypes (V and VI) (Figs. 2.2a and 2.4a) [2, 3].

b

Fig. 2.1  Plaque-type psoriasis of the knee in a Caucasian woman (a). Dermoscopy reveals diffuse white scales; vessels are not visible as they are covered by the scaling (b)

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Fig. 2.2  Plaque-type psoriasis of the knee in an Indian woman (a). Dermoscopic examination shows uniform dotted vessels (magnified in the inset) over a reddish-pinkish background; white and brown structureless areas are also evident (b)

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Fig. 2.3  Severe plaque-type psoriasis in a Caucasian boy (a). Uniform dotted vessels are the predominant dermoscopic feature (b)

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Fig. 2.4  Plaque-type psoriasis in an African man typified by gray hyperkeratotic plaques of the abdomen (a). Dermoscopy reveals diffuse white scales and brown background with no vessels (b)

Several other forms of psoriasis may be observed in both fair and dark skin, such as nail psoriasis (pitting, crumbling, Beau lines, etc.), guttate psoriasis (abrupt onset of scaly papules often following a streptococcal pharyngitis) (Figs.  2.5a and 2.6a), erythrodermic psoriasis (erythema and scaling involving >90% of the body surface), palmoplantar or generalized pustular psoriasis (pinpoint sterile pustules on an erythematous background) (Fig.  2.7a), inverse psoriasis (well-demarcated plaques

with little or no scaling affecting the skin creases), follicular psoriasis (follicular keratotic/scaly papules) (Fig. 2.8a), and hyperkeratotic (psoriasis ostracea and psoriasis rupioides) or figurate (psoriasis gyrata and annular psoriasis) variants [2, 3]. However, some clinical forms may present a different prevalence according to ethnic factors (e.g., pustular psoriasis is more common in Asian populations, while follicular psoriasis is more frequent people of African descent) [2–5].

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E. Errichetti

a

b

Fig. 2.5  Guttate psoriasis in a Caucasian boy (a). Uniform dotted vessels over a red background are seen on dermoscopic examination (b)

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Fig. 2.6  Guttate psoriasis in an African girl (a). Dermoscopy displays diffuse white scales and uniform dotted vessels (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

2.1.3 Dermoscopy Psoriasis presents two typical dermoscopic features, i.e., diffuse white scales and uniform dotted vessels (Figs. 2.1b, 2.2, 2.3, 2.4, 2.5 and 2.6b), respectively, representing hyperkeratosis and the tips of dilated vessels in the elongated dermal papillae from a histological point of view [6–10]. Notably, scaling may cover underlying vascular structures in hyperkeratotic lesions (Fig. 2.1a); therefore, only removal of the scales (e.g., by using a liquid medium) may reveal the typical

psoriatic vessels (Fig. 2.3b) [6, 9]. Importantly, scaling pattern may be the only evaluable parameter in skin of color since the dark background may mask any vascular finding despite scale removal (Fig.  2.4b), especially in areas with thick skin (i.e., scalp or palmoplantar surface) or initial/thin lesions as they are histologically typified by a scarce papillomatosis [10]. However, the characteristic vascular pattern may still be visible in a significant proportion of dark-skinned patients (around two-thirds of cases) (Figs. 2.2b and 2.6b) as the marked epidermal acanthosis typical of psoriasis can

2  Common Papulosquamous Disorders

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Fig. 2.7  Pustular psoriasis in a light-skinned (phototype III) Asian lady (a). Several round yellow pustules along with white scales, hemorrhagic dots, and uniform dotted vessels are evident on dermoscopic examination (b)

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Fig. 2.8  Follicular psoriasis in an Indian boy (a). Dermoscopic assessment shows perifollicular white scales (magnification in the inset) (b)

make the skin background lighter, thereby enhancing the optical contrast with vessels [7, 8]. Additional dermoscopic findings visible in psoriasis include focal structureless white areas (corresponding to ­epidermal acanthosis), hemorrhagic dots/areas, and erosions/ broken hairs resulting from scratching [6–10]. Moreover, pigmentary features (i.e., focal or diffuse structureless areas) are also frequently found in dark phototypes due to basal layer hyperpigmentation (Fig. 2.2b) [7, 10]. The dermoscopic appearance of other variants of psoriasis usually does not significantly differ from plaque-type psoriasis, except for the scaling amount [6–10]. For example,

inverse psoriasis and psoriatic balanitis typically do not feature scales, while scalp and palmoplantar psoriasis commonly reveal a thick hyperkeratotic surface [6–10]. However, there are some forms of psoriasis that may show some peculiarities, such as pustular psoriasis, also showing white/yellow globules (Fig.  2.7b), rupioid psoriasis, typified by cone-shaped thick scales, and follicular psoriasis, featuring irregularly distributed follicular plugs and/or white perifollicular scaling (Fig. 2.8b) [9, 10]. All these forms of psoriasis usually do not show relevant differences according to phototypes, apart from the lower prevalence of vessels in very dark skin [9, 10].

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2.2 Dermatitis 2.2.1 Introduction The term “dermatitis” encompasses a group of inflammatory dermatoses with different etiopathogeneses that are typified by itchy eczematous lesions displaying spongiosis on histology [9, 10]. Several clinical subtypes of dermatitis do exist, with allergic contact dermatitis and atopic dermatitis being the most common forms in both fair- and dark-skinned subjects [9, 10]. Notably, in the latter group of patients, atopic dermatitis represents one of the most frequent reasons for referral to a dermatologist [11].

2.2.2 Clinical Presentation

2.2.3 Dermoscopy

Disease stage affects the clinical presentation of dermatitis [9–11]. In particular, acute lesions typically manifest as ill-­defined erythematous-edematous patches, with or without overlying pinpoint vesicles and/or serous drainage, while crusted/scaly and lichenified patches, respectively, characterize the subacute and chronic phases [9–11]. Compared to fair phototypes (Figs.  2.9a and 2.10a), erythema may be difficult to appreciate in skin of color, so crusting and scaling may sometimes be the only clinical features in acute/subacute lesions (Figs. 2.11a and 2.12a), while lichenified chronic plaques usually show a violaceous/brown and dark brown/gray shade in lighter and darker phototypes, respectively (Figs.  2.13a and 2.14a) [9–11].

a

Lesions localization differs according to the subtype of dermatitis, with allergic contact dermatitis typified by a distribution pattern depending on the area of contact with the hapten (Fig. 2.12a), stasis dermatitis displaying eczematous patches on the legs, and atopic dermatitis mainly involving face and extensor extremities (Figs. 2.9a and 2.11a) in infants and hands/flexures in childhood/adults. Palmoplantar lesions may be due to either allergic contact or atopic dermatitis (Figs. 2.15a and 2.16a) [9–11]. Several variants of atopic dermatitis do exist, including nummular eczema (roundish eczematous lesions) (Fig.  2.10a), papular eczema (Fig.  2.17a), and follicular eczema (Fig. 2.18a), with the last two forms being far more frequent in darker phototypes [10].

Similarly to clinical morphology, dermoscopic findings of dermatitis vary according to the disease stage [9, 10]. In detail, patchy yellow scales/crusts, resulting from hyperkeratosis and spongiosis/serum exudation, are the main features of acute and subacute phases regardless of patient’s phototype (Figs. 2.9, 2.10, 2.11 and 2.12b) [6, 7, 9, 10]. Notably, adherent fabric fibers (Figs.  2.10b, 2.11 and 2.12b) sometimes represent the only sign of serum exudation [6, 7, 9, 10], while eczematous lesions of palmoplantar areas often also feature spongiotic vesicles (browngray globules) due to the presence of a thicker epidermis that makes them less prone to break (Figs.  2.15b and 2.16b) [10, 12]. Additionally, clustered dotted vessels are

b

Fig. 2.9  Atopic dermatitis of the cubital fold in a Caucasian boy (a). Dermoscopy reveals yellow scales/crusts along with clustered dotted vessels (b)

2  Common Papulosquamous Disorders

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a

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Fig. 2.10  Nummular eczema of the dorsal aspect of the finger in a Caucasian lady (a). White and yellow scales/crusts along with clustered dotted vessels and fabric fibers are visible on dermoscopic examination (b)

a

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Fig. 2.11  Atopic dermatitis of the cubital fold in an African boy (a). Dermoscopy shows white and brown scales/crusts over a brown background along with few fabric fibers (arrowhead) (b)

frequently seen in fair-skinned patients (Figs.  2.9b and 2.10b), while they are usually absent in skin of color, in which it is often possible to detect patchy brownish scales/ crusts as a result of hyperkeratosis, spongiosis, and melanin exfoliation (Figs. 2.11b and 2.12b) [7, 10]. Less specific dermoscopic features of subacute stages include patchy white scales and hemorrhagic areas/dots/ crusts (resulting from scratching) (Fig. 2.11b) [6, 7, 9, 10]. Moreover, perifollicular scaling, focal structureless white areas (corresponding to epidermal acanthosis), and pigmentary findings (e.g., focal structureless brown/gray areas due to basal layer pigmentation and brown dots due to pigment

incontinence) are also frequently observed in ethnic skin (Figs. 2.11b and 2.12b) [7, 10]. The most common findings of chronic lichenified eczematous lesions include diffuse white scaling due to hyperkeratosis, patchy or diffuse dotted vessels surrounded by a white halo resulting from dermal papillae vessels dilation and epidermal acanthosis, and scratching-related changes (i.e., hemorrhagic areas/dots and crusts, broken hair, and superficial erosions) (Fig. 2.13b) [6, 9]. Of note, vessels may be absent in very dark skin, which often shows white structureless areas (corresponding to epidermal acanthosis and fibrosis) and pigmentary structures (focal structureless brown/gray

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b

Fig. 2.12  Allergic contact dermatitis of the abdomen in an African boy (a). Dermoscopic assessment reveals focal structureless white areas, fabric fibers (arrowhead), and yellow/brown scales/crusts (b)

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b

Fig. 2.13  Lichenified eczema of the shin in an elderly Caucasian woman (a). Diffuse white scales, patchy yellow crusts, and focally distributed dotted vessels with white halo (magnification in the inset) are seen on dermoscopy (b)

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b

Fig. 2.14  Lichenified atopic dermatitis of the thighs in an African girl (a). Dermoscopic examination displays brown background, white structureless areas (arrowhead), and patchy brown scales/crusts (b)

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Fig. 2.15  Chronic hand eczema in a Caucasian woman (a). Dermoscopy shows yellow scales/crusts and spongiotic vesicles that look like salmon-­ colored globules (arrowheads) (b)

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Fig. 2.16  Chronic hand eczema in an Indian man (a). Dermoscopic assessment reveals white and yellow scales/crusts and spongiotic vesicles that look like brown globules (arrowheads) (b). (Courtesy of Balachandra S. Ankad, MD – Bagalkot, India)

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b

Fig. 2.17  Papular eczema in an African boy (a). Several papules showing a central round yellow crust surrounded by a white halo displaying peripheral white projections (magnification in the inset) are evident on

a

dermoscopy (b). (From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

b

Fig. 2.18  Follicular eczema in an African boy (a). Dermoscopy reveals equidistant follicular hyperkeratosis with a white halo (b)

areas and brown dots) (Fig.  2.14b) [10]. Patchy yellow/ brown scales/crusts and follicular plugs (representing follicular hyperkeratosis) are additional possible findings seen in both fair- and dark-skinned patients (Fig. 2.14b) [6, 7, 9, 10]. Finally, some clinical variant may display dermoscopic peculiarities. In detail, papular eczema typically shows

roundish white areas with peripheral striae (“white starburst” pattern), often with a central yellow crust (Fig. 2.17b), while follicular eczema features regularly distributed follicular plugs (corresponding to follicular hyperkeratosis) surrounded by a white halo (resulting from epidermal acanthosis) (Fig. 2.18b) [7, 10].

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2.3 Lichen Planus

2.3.2 Clinical Presentation

2.3.1 Introduction

The main clinical variants of LP in both fair and ethnic skin include classic and hypertrophic subtypes; additionally, actinic Lichen planus (LP) is an inflammatory condition that may LP is also quite frequent in dark phototypes [9, 10, 14]. affect the skin, mucosae, and/or nails which has been related Classic LP typically manifests with itchy polygonal, to an autoimmune reaction mediated by T cells to altered flat-­topped papules sometimes coalescing into plaques that self-antigens on basal keratinocytes [9, 13]. It is more com- most commonly affect wrists, forearms, dorsal aspects of mon in middle-aged adults, and no significant racial predis- the hands, and pretibial areas, albeit they may involve any position has been reported, though its incidence in skin of body area (Figs. 2.19a and 2.20a) [9, 10, 14]. Of note, the color may be variable, with figures of 0.29% in African-­ shade of the lesions remarkably varies based on the skin Americans and 0.1–1% in East Indians [10, 14]. type, with lighter skin being typified by violaceous papules

a

b

Fig. 2.19  Lichen planus in a Caucasian man (a). The typical white crossing lines creating a network-like structure (Wickham striae) surrounded by dotted vessels are visible on dermoscopic examination (b)

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Fig. 2.20  Lichen planus in an African man (a). Wickham striae are seen as light blue reticular lines on dermoscopy (b)

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(Fig. 2.19a) and darker phototypes by brownish, grayish, or blackish papules (Fig.  2.20a) [9, 10, 14]. Post-healing hyperpigmentation may be seen in both fair and dark skin (Figs. 2.21a and 2.22a), though it is far more common and marked in the latter [9, 10, 14]. Oral mucosa is often involved in classic LP with lesions composed by white crossing lines [9, 10, 14]. Hypertrophic LP is typified by very itchy, thick, violaceous (fair skin), or brownish (dark skin) plaques with a grayish hyperkeratotic surface usually affecting the pretib-

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ial areas (Figs. 2.23a and 2.24a), while actinic LP usually presents with annular hyperpigmented plaques with a purple/white border involving sun-exposed areas (Fig. 2.25a); less common clinical variants of actinic LP include melasma-­like, dyschromic, and classic lichenoid subtypes [9, 10, 14]. Several less common forms of LP do exist, including bullous LP, follicular LP, LP pemphigoides, blaschkolinear LP, annular LP, atrophic LP, ulcerative LP, and LP-lupus erythematosus overlap syndrome [9, 10, 14].

b

Fig. 2.21  Post-healing hyperpigmentation due to lichen planus in a Caucasian woman (a). Dermoscopic assessment shows brown-gray peppering (b)

a

b

Fig. 2.22  Hyperpigmented macules in the healing stage of lichen planus in an African man (a). Dermoscopy displays diffuse brown pigmentation along with a peripheral annular representing Wickham striae (b)

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b

Fig. 2.23  Hypertrophic lichen planus of the legs in a Caucasian man (a). Dermoscopic examination shows gray follicular plugs (arrowheads), white scaling, and sparse dotted vessels (b)

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Fig. 2.24  Hypertrophic lichen planus of the legs in an Indian man (a). Dermoscopy reveals dark gray follicular plugs (arrowheads) over a dark violaceous background; Wickham striae are also evident (b). (Courtesy of Balachandra S. Ankad, MD – Bagalkot, India)

2.3.3 Dermoscopy The main dermoscopic clue of classic LP in its active stages is represented by the so-called Wickham striae, which are due to the presence of hypergranulosis on histology [6, 7, 9, 10]. They typically manifest as intersecting crossing white (fair skin) or bluish-white (dark skin) lines forming a net-

work (Figs. 2.19b and 2.20b), although other morphologies may be observed, including linear, annular, round, “leaf venation”-like (mimicking the crystal structure of snow), and “starry sky”-like (clustered, follicular white dots) [6, 7, 9, 10]. Additionally, peripheral dotted and/or linear vessels are commonly seen in Caucasians (Fig. 2.19b), while they are observed only in a minority of cases in skin of color

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Fig. 2.25  Lichen planus actinicus in an African boy (a). Follicular plugs over a brown background is the typical dermoscopic feature of this variant of lichen planus (b)

(Fig.  2.20b) [6, 7, 9, 10]. On the other hand, pigmentary structures (i.e., structureless brown areas resulting from basal layer hyperpigmentation and brown/gray dots related to dermal melanophages/melanin incontinence) are more frequent (especially structureless brown areas), marked, and persistent in dark phototypes (Fig.  2.21b) compared to lighter phototypes (Fig. 2.22b) [6, 7, 9, 10]. Notably, they may be the predominant or the sole feature in healing and post-­inflammatory lesions of classic LP (Figs.  2.21b and 2.22b) [6, 7, 9, 10]. Hypertrophic LP in both fair- and dark-skinned patients mainly reveals white-gray or brown (especially in skin of color) follicular plugs histologically related to follicular hyperkeratosis; sparse dotted vessels may also be seen in lighter phototypes (Figs. 2.23b and 2.24b) [6, 7, 9, 10]. In this clinical subtype, Wickham striae are usually absent as they are covered by the overlying hyperkeratosis, while they are generally visible as a peripheral white halo in LP actinicus, yet the most characterizing feature is the presence of follicular plugs over a brown background (Fig. 2.25b) [6, 7, 9, 10].

2.4 Pityriasis Rosea 2.4.1 Introduction Pityriasis rosea (PR) is a common inflammatory dermatosis typically affecting adolescents and young adults that is characterized by a self-limiting course with a duration of

6–10 weeks [15–17]. No gender and racial predilection have been reported [15–17]. Even though its etiology is not ­completely clear, some authors have speculated a possible association with herpes viruses types 6/7 [15–17].

2.4.2 Clinical Presentation PR is usually typified by the onset a single “herald” or “mother” lesion consisting of an oval inflammatory patch with a scaling collarette showing an inner free edge that is followed after a few days by the occurrence of several asymptomatic or itchy “secondary” lesions, which may be either papules or oval scaling patches similar to the herald patch (Figs. 2.26a and 2.27a) [9, 10, 15–17]. The main difference according to the phototype is the background color of the lesions, with fair-skinned patients showing a reddish hue and ethnic skin featuring a brownish/ gray shade (Figs. 2.26a and 2.27a) [9, 10, 15–17]. Moreover, papular variants (without patches) (Fig.  2.28a) and post-­ inflammatory hyper- or, less commonly, hypopigmentation (Fig. 2.29a) are by far more common in skin of color [9, 10, 15–17]. PR typically involves proximal extremities and trunk (where lesions arrangement is frequently parallel to the lines of cleavage giving rise to a “Christmas tree” distribution) [9, 10, 15–17]. Nevertheless, face localization and inverse ­distribution (neck, axilla, groin, and lower abdomen) may be seen, especially in dark-skinned patients [9, 10, 15–17].

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Fig. 2.26  Pityriasis rosea in a Caucasian boy (a). Dermoscopy displays an elongated peripheral white scaling with a jagged and inner free edge over a red background (b)

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Fig. 2.27  Pityriasis rosea in an African girl (a). Dermoscopy shows an elongated peripheral white scaling with a jagged and inner free edge over a brown background along with brown dots (b)

2.4.3 Dermoscopy The dermoscopic hallmark of both herald and secondary lesions of PR consists of a peripheral collarette of white scales with a jagged inner free edge, histologically corresponding to focal parakeratosis in mounds (Figs.  2.26b and 2.27b) [6, 7, 9, 10]. Of note, this dermoscopic feature may sometimes be lacking in skin of color, especially in

lesions located on the face that often show a perifollicular scaling pattern [6, 7, 9, 10]. Furthermore, sparse vessels (mainly dotted) may be seen in Caucasians, while darkskinned patients may display focal or diffuse (as a background) brown structureless areas (Fig.  2.27b) resulting from basal layer hyperpigmentation and brown dots corresponding to dermal pigment incontinence [6, 7, 9, 10].

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Fig. 2.28  Papular pityriasis rosea in an African boy (a). Ill-defined non-follicular white areas are evident on dermoscopic assessment (b). (From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

a

b

Fig. 2.29  Post-inflammatory hyperpigmentation in a Caribbean woman (a). Dermoscopy shows brown reticular structures (b)

Additional dermoscopic features of PR in ethnic skin include peripheral brown scales (resulting from hyperkeratosis, spongiosis, and melanin exfoliation) and focal gray structureless areas (corresponding to basal layer hyperpigmentation and slight acanthosis) [7, 10]. Finally, papular PR (Fig. 2.28b) is typified by white structureless areas with ill-defined margins that may be centered around follicles, whereas post-inflammatory hyperpigmented lesions (Fig.  2.29b) generally reveal structureless brown areas or brown network [10].

2.5 Lichen Simplex Chronicus and Lichenification 2.5.1 Introduction Lichenification is a term to describe thickening of the skin related to a repetitive and chronic scratching or rubbing due to localized chronic pruritus [9, 10]. It may occur as consequence of an eczematous dermatitis/other inflammatory itchy dermatoses (secondary lichenification) or without any

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underlying skin condition (lichen simplex chronicus—LSC) [9, 10].

2.5.2 Clinical Presentation

skin is usually red or purple (Figs. 2.30a and 2.31a), dark-­ skinned patients usually show a brownish or white (macerated areas) hue (Figs. 2.32a and 2.33a) [9, 10].

2.5.3 Dermoscopy

From a clinical point of view, LSC manifests as solitary (most commonly) or multiple well-defined leathery scaling/ keratotic plaques displaying accentuated skin markings (Figs. 2.30a, 2.31, 2.32 and 2.33a) [9, 10]. Dorsal aspects of the hands/feet, forearms, pretibial areas, nape of the neck, and anogenital area are the most frequently involved sites [9, 10]. Notably, whereas the background of the lesions in fair a

The most characterizing finding of LSC consists of dotted vessels distributed in a patchy or diffuse (most commonly) pattern histologically corresponding to the tips of dilated capillaries in dermal papillae (Figs.  2.30b and 2.31b) [9, 10]. Differently from psoriasis, such vascular structures are usually surrounded by a white halo (Figs. 2.30b and 2.31b) resulting from hyperb

Fig. 2.30  Lichenified eczematous lesion in a Caucasian man (a). Dotted vessels with a white halo (magnification in the inset) along with white and yellow scales/crusts are visible on dermoscopy (b)

a

b

Fig. 2.31  Lichen simplex chronicus of the legs in a Caucasian man (a). Follicular plugs surrounded by dotted vessels with a white halo along with hemorrhagic dots are seen on dermoscopy (b)

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Fig. 2.32  Lichen simplex chronicus of the right sacral area in an African man (a). Dermoscopic assessment shows bright white areas, pigmented brown areas, and hemorrhagic dots/areas (b)

a

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Fig. 2.33  Lichen simplex chronicus of the left groin in an African man (a). Dermoscopy displays follicular plugs as well as white and brown areas (b)

granulosis, which is typical of LSC [9, 10]. Notably, due to the pigmented background, vessels may not be seen in very dark phototypes (Figs. 2.32b and 2.33b), so dermoscopic diagnosis relies on nonvascular findings [9, 10]. Hemorrhagic areas/dots and crusts, broken hairs, and superficial erosions are typical nonvascular features of LSC in both fair and dark skin (Figs.  2.30b and 2.32b) [9, 10]. Further possible dermoscopic findings include follicular plugs corresponding to follicular hyperkeratosis and white structureless areas resulting from dermal fibrosis (Figs. 2.31b, 2.32 and 2.33b) [9, 10]. The latter feature is more common and accentuated in skin of color due to a higher tendency to fibrotic reaction compared to lighter phototypes (Fig. 2.32b) [9, 10]. Additionally, pigmentary structures, including brown structureless areas due to basal layer hyperpigmentation and

brown/gray dots related to dermal melanophages, are also frequently seen in skin of color (Figs. 2.32b and 2.33b) [9, 10]. Importantly, typical dermoscopic findings of the underlying dermatoses may also be found in secondary lichenification, e.g., yellow scales/crusts in forms associated to eczematous dermatitis (Fig. 2.30b) [9, 10].

2.6 Frictional Lichenoid Dermatitis 2.6.1 Introduction Frictional lichenoid dermatitis (FLE) is a clinical entity related to repeated friction/trauma of the skin which is considered by some authors as a dermatosis related to sunlight exposure and/

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or atopic dermatitis [18]. It is more common in skin of color, yet it may also be seen in lighter phototypes [9, 10, 18].

2.6.3 Dermoscopy

From a dermoscopic point of view, FLE shows a whitish background presenting ill-defined and radiating borders his2.6.2 Clinical Presentation tologically related to acanthosis and hypergranulosis (Figs. 2.34b and 2.35b) [9, 10]. Uniform dotted vessels are FLE is clinically typified by multiple, pinhead-sized, skin-­ another typical feature, though they are more evident in fair-­ colored, or hypopigmented (especially in dark skin) papules skinned patients (Fig. 2.34b) [9, 10]. Further findings include which often tend to coalesce (Figs.  2.34a and 2.35a) [18]. hemorrhagic dots/spots and crusts (Figs.  2.34b and 2.35b) The most commonly involved sites include elbows, dorsal [9, 10]. aspect of the hands, and knees [18].

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Fig. 2.34  Frictional lichenoid dermatitis in a Caucasian girl (a). Dermoscopic examination shows ill-defined white areas with uniform dotted vessels (magnification in the inset); small hemorrhagic crust are also seen (b)

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Fig. 2.35  Frictional lichenoid dermatitis in a Caucasian girl (a). Dermoscopy reveals ill-defined white areas with radiating borders (magnification in the inset); small hemorrhagic crust are also seen (b)

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References 1. Rendon A, Schäkel K. Psoriasis pathogenesis and treatment. Int J Mol Sci. 2019;20:1475. 2. Geng A, McBean J, Zeikus PS, McDonald CJ. Psoriasis. In: Kelly AP, Taylor SC, editors. Dermatology for skin of color. 1st ed. New York: McGraw-Hill Medical; 2009. p. 139–46. 3. Thorpe R, Pandya AG. Psoriasis. In: Jackson-Richards D, Pandya AG, editors. Dermatology atlas for skin of color. 1st ed. Berlin: Springer; 2014. p. 131–8. 4. Komatsuda S, Kamata M, Chijiwa C, et al. Gastrointestinal bleeding with severe mucosal involvement in a patient with ­generalized pustular psoriasis without IL36RN mutation. J Dermatol. 2019;46:73–5. 5. Arps DP, Chow C, Lowe L, Chan MP. Follicular psoriasis. J Cutan Pathol. 2013;40:859–62. 6. Errichetti E.  Dermoscopy of inflammatory dermatoses (inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80. 7. Errichetti E, Ankad BS, Sonthalia S, et  al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the International Dermoscopy Society. Eur J Dermatol. 2020;30:688–98. 8. Nwako-Mohamadi MK, Masenga JE, Mavura D, Jahanpour OF, Mbwilo E, Blum A. Dermoscopic features of psoriasis, lichen planus, and Pityriasis Rosea in patients with skin type IV and darker attending the regional dermatology training Centre in northern Tanzania. Dermatol Pract Concept. 2019;9:44–51.

E. Errichetti 9. Lallas A, Errichetti E.  Papulosquamous disorders. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 2–46. 10. Errichetti E, Ankad B, Neema S, et al. Papulosquamous disorders. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 3–28. 11. Desai N, Alexis AF. Atopic dermatitis and other eczemas. In: Kelly AP, Taylor SC, editors. Dermatology for skin of color. 1st ed. New York: McGraw-Hill Medical; 2009. p. 163–6. 12. Errichetti E, Stinco G. Dermoscopy in differential diagnosis of palmar psoriasis and chronic hand eczema. J Dermatol. 2016;43:423–5. 13. Weston G, Payette M. Update on lichen planus and its clinical variants. Int J Womens Dermatol. 2015;1:140–9. 14. Condie D, Pandya AG.  Lichen planus, Nitidus, and Striatus. In: Jackson-Richards D, Pandya AG, editors. Dermatology atlas for skin of color. 1st ed. Berlin: Springer; 2014. p. 115–22. 15. Leung AKC, Lam JM, Leong KF, Hon KL.  Pityriasis Rosea: an updated review. Curr Pediatr Rev. 2020;17:201–11. https://doi.org/ 10.2174/1573396316666200923161330. 16. Shabazz DR.  Pityriasis Rosea. In: Kelly AP, Taylor SC, editors. Dermatology for skin of color. 1st ed. New  York: McGraw-Hill Medical; 2009. p. 147–51. 17. Jackson-Richards D.  Pityriasis Rosea. In: Jackson-Richards D, Pandya AG, editors. Dermatology atlas for skin of color. 1st ed. Berlin: Springer; 2014. p. 123–6. 18. Sardana K, Goel K, Garg VK, et al. Is frictional lichenoid dermatitis a minor variant of atopic dermatitis or a photodermatosis. Indian J Dermatol. 2015;60:66–73.

3

Less Common Papulosquamous Disorders Enzo Errichetti, Nkechi A. Enechukwu, and Payal Chauhan

Contents 3.1 3.1.1  3.1.2  3.1.3 

Pityriasis Lichenoides  Introduction  Clinical Presentation  Dermoscopy 

 28  28  28  28

3.2 3.2.1  3.2.2  3.2.3 

 ityriasis Rubra Pilaris  P Introduction  Clinical Presentation  Dermoscopy 

 31  31  31  32

3.3 3.3.1  3.3.2  3.3.3 

Porokeratosis  Introduction  Clinical Presentation  Dermoscopy 

 33  33  33  36

3.4 3.4.1  3.4.2  3.4.3 

Lichen Nitidus  Introduction  Clinical Presentation  Dermoscopy 

 36  36  36  36

3.5 3.5.1  3.5.2  3.5.3 

Lichen Striatus  Introduction  Clinical Presentation  Dermoscopy 

 38  38  38  38

3.6 3.6.1  3.6.2  3.6.3 

Lichen Spinulosus  Introduction  Clinical Presentation  Dermoscopy 

 41  41  41  41

3.7 3.7.1  3.7.2  3.7.3 

Keratosis Pilaris  Introduction  Clinical Presentation  Dermoscopy 

 42  42  42  42

References 

 43

E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy N. A. Enechukwu Dermatology Unit, Department of Internal Medicine, Nnamdi Azikiwe University, Awka, Nigeria P. Chauhan Department of Dermatology, Venereology and Leprosy, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Dehradun, India © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_3

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3.1 Pityriasis Lichenoides 3.1.1 Introduction Pityriasis lichenoides is a spectrum of self-limiting skin disorders usually lasting for an average of 18–20 months that includes two main clinicopathological subtypes, i.e., ­pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica (PLC) [1–3]. Even though its etiopathogenesis is still not completely clear, bacterial and viral agents have been speculated to act as triggers by activating an inflammatory response via T-cell mediation and immune complex induction [1–3]. Both PLEVA and PLC most commonly occur during the first three decades of life without any racial predilection [1–3].

3.1.2 Clinical Presentation PLEVA typically presents as asymptomatic or burning/itching inflammatory papules whose center tends to become vesiculopustular, hemorrhagic, necrotic, ulcerated, or crusted (Figs. 3.1a, 3.2, 3.3 and 3.4a) [1–3]. Trunk and arms are the most frequently involved areas, while face, palms, and soles are commonly spared [1–3]. Color of the papules usually varies according to phototype, with light- and dark-skinned patients showing a pink/reddish (Figs.  3.1a and 3.2a) and brown shade (Figs.  3.3a and 3.4a), respectively [1–3]. Of note, lesions often regress spontaneously leaving residual hypo/hyperpigmentation or varioliform scars that are more common in skin of color [1–3].

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PLC manifests as asymptomatic pink/red or brown (darker phototypes) papules covered by uniform white scaling or a single centrally attached white scale (mica-like scale) commonly falling off spontaneously or by scraping (Figs. 3.5a, 3.6 and 3.7a) [1–3]. Similarly to PLEVA, lesions tend to involve trunk and arms and occur in crops, thus giving rise to a polymorphic appearance with lesions in different phases [1–3]. Hypopigmented macules may be seen after healing of the papules, especially in dark-skinned patients, in whom they may be the sole manifestation of PLC [1–3].

3.1.3 Dermoscopy Dermoscopic findings of PLEVA remarkably vary based on lesion stage and skin phototype [1, 3–7]. In particular, in fair-­ skinned patients, early and mature lesions, respectively, feature purpuric areas resulting from erythrocyte extravasation (Fig.  3.1b) and a central amorphous brownish crust due to epidermal necrosis (Fig. 3.2b), whereas healing lesions commonly show a central white area histologically corresponding to fibrosis [1, 3–7]. On the other hand, in darker phototypes, purpuric areas are seen less frequently, and a central necrotic brownish-black crust surrounded by a peripheral white structureless area (sometimes displaying radial white streaks) due to epidermal acanthosis is the main finding (Figs.  3.3b and 3.4b) [1, 3–7]. Moreover, a peripheral scaling collarette with an inner free edge is commonly seen in all lesions stages regardless the phototype (Figs. 3.1b, 3.2, 3.3 and 3.4b), while a peripheral rim of dotted/linear vessels (Fig. 3.2b) and pigmentary structures (bluish-greyish globules/structureless areas corresponding to melanin pigment/melanophages in the b

Fig. 3.1  Pityriasis lichenoides et varioliformis acuta in a Caucasian man (a). Dermoscopy reveals purpuric areas and a peripheral scaling collarette with an inner free edge (b)

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a

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Fig. 3.2  Pityriasis lichenoides et varioliformis acuta in a Caucasian boy (a). Dermoscopic examination shows a central amorphous brownish crust with a peripheral scaling collarette with an inner free edge surrounded by dotted vessels (b)

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Fig. 3.3  Pityriasis lichenoides et varioliformis acuta in an African boy (a). A central necrotic brownish-black crust surrounded by a scaling white collarette with an inner free edge and a peripheral white halo is seen on dermoscopy (b)

dermis) (Fig.  3.4b) may be evident mainly in lighter and darker phototypes, respectively [1, 3–7]. The hallmark of PLC in lighter phototypes is represented by the presence of orange structureless areas (corresponding to hemosiderin deposits in the dermis due to erythrocyte extravasation) with or without blurred non-dotted vessels (including globular, linear-irregular, and/or branching vessels) (Fig. 3.5b) [1, 3–7]. Notably, orange areas are difficult to see in dark-skinned patients, who mainly feature a peripheral white scaling collarette with an inner smooth free edge

(resulting from hyperkeratosis) (Fig. 3.6b) along with diffuse or focal brown structureless areas (due to basal layer pigmentation and dermal hemosiderin deposits) (Fig. 3.7b) [1, 3–7]. Additional dermoscopic findings include sparse dotted vessels, hemorrhagic spots, central micaceous scale, brown dots (in darker phototypes due to pigment incontinence in the dermis) (Fig. 3.7b), and hypopigmented areas (Fig. 3.7b), with this last feature being more common in longstanding lesions as a result of focal post-inflammatory hypopigmentation [1, 3–7].

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Fig. 3.4  Pityriasis lichenoides et varioliformis acuta in an African girl (a). Dermoscopic assessment displays a brown crust containing brown dots and surrounded by a white halo (b)

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Fig. 3.5  Pityriasis lichenoides chronica in a Caucasian boy (a). Dermoscopy shows a diffuse orange structureless area and peripheral white scales (b)

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b

Fig. 3.6  Pityriasis lichenoides chronica in an African girl (a). A central white mica-like scale and peripheral smooth white scaling collarette are seen on dermoscopy along with purpuric dots/areas (b). (From

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“Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

b

Fig. 3.7  Pityriasis lichenoides chronica in an Indian boy (a). Dermoscopic examination shows brown background and brown dots; a peripheral post-inflammatory hypopigmented area is also evident (b)

3.2 Pityriasis Rubra Pilaris

3.2.2 Clinical Presentation

3.2.1 Introduction

Five clinical variants are classically reported, including classical (adult onset [type I] and juvenile onset [type III]), atypical (adult onset [type II] and juvenile onset [type V]), and circumscribed juvenile (type IV) [1, 3, 8]. Classical subtypes manifest as follicular hyperkeratotic papules and scaly inflammatory patches spreading in a cephalocaudal pattern (Figs.  3.8a and 3.9a) [1, 3, 8]. Erythroderma typified by areas of uninvolved skin (islands of sparing), palmoplantar keratoderma, and nail changes are other possible manifestations [1, 3, 8]. Atypical

Pityriasis rubra pilaris (PRP) is a chronic papulosquamous dermatosis with an unknown etiology, though streptococcal infections, vaccinations, and medications have been speculated to be possible antigenic triggers [1, 3, 8]. No gender or racial predilection has been reported; albeit hereditary forms do exist, it is usually sporadic, with a bimodal age distribution, with peaks in the first and fifth decades [1, 3, 8].

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Fig. 3.8  Pityriasis rubra pilaris (classical adult type) in a Caucasian man (a). Dermoscopy displays multiple orange structureless areas surrounded by dotted and linear vessels (b)

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Fig. 3.9  Pityriasis rubra pilaris (classical juvenile type) in an African boy (a). Dermoscopic examination reveals white follicular plugs (b)

forms show follicular hyperkeratosis and either ichthyosiform lesions on the legs along with sparse scalp hair (adult onset) or scleroderma-like change of the hands and feet (juvenile onset) [1, 3, 8]. Finally, circumscribed juvenile PRP presents as scaly erythematous (psoriasis-­like) plaques involving elbows and knees, with or without palmoplantar keratoderma (Figs. 3.10a and 3.11a) [1, 3, 8]. The most remarkable difference between fair- and dark-skinned patients is the diverse shade of erythema, being salmon-colored in the former and violaceous/brownblack in the latter (Figs. 3.8a, 3.9, 3.10 and 3.11a) [1, 3, 8].

3.2.3 Dermoscopy The main dermoscopic finding of PRP consists of follicular scaling/plugs histologically corresponding to follicu-

lar hyperkeratosis (Figs. 3.8b, 3.9, 3.10 and 3.11b) [1, 3, 4, 6, 7]. A perifollicular yellow-orange halo or orange focal structureless areas due to dermal hemosiderin deposits may also be evident in lighter phototypes (Figs. 3.8b and 3.10b), whereas they are less commonly seen in very dark skin (Figs. 3.9b and 3.11b) [1, 3, 4, 6, 7]. However, orange structureless areas may be found on palms and soles of dark-­skinned patients in case of keratoderma as palmoplantar areas show a lighter tone compared to other anatomical sites [1, 3, 4, 6, 7]. Notably, characteristic islands of non-­erythematous (spared) skin displaying reticular vessels may be observed in erythrodermic forms in fair skin [1, 3, 4, 6, 7]. Other less specific dermoscopic findings include patchy whitish scales and scattered dotted/linear vessels (fair skin) (Fig.  3.8b and 3.10b) [1, 3, 4, 6, 7].

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Fig. 3.10  Circumscribed juvenile pityriasis rubra pilaris in a Caucasian boy (a). Follicular plugs with perifollicular yellow-orange halo (arrowheads) along with patchy white scales and some dotted/linear vessels are evident on dermoscopy (b)

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Fig. 3.11  Circumscribed juvenile pityriasis rubra pilaris in an Indian boy (a). Follicular plugs with subtle perifollicular yellow halo (arrowheads) along with some patchy white scales (b)

3.3 Porokeratosis 3.3.1 Introduction Porokeratosis is a term encompassing a heterogenous group of genodermatoses histologically typified by the so-called cornoid lamella clinically resulting in a peripheral keratotic rim [1, 3, 9]. Porokeratosis is more commonly seen in fair than dark skin [1, 3, 9].

3.3.2 Clinical Presentation Four main clinical subtypes are classically recognized, i.e., disseminated actinic porokeratosis, porokeratosis of

Mibelli, linear porokeratosis, and disseminated porokeratosis, with the first two forms being the most frequently encountered ones [1, 3, 9]. All such variants are typified by slightly raised papules/plaques featuring a peripheral keratotic rim (Figs. 3.12a, 3.13, 3.14, 3.15 and 3.16a) [1, 3, 9]. Lesions are single or few in porokeratosis of Mibelli (Figs.  3.15a and 3.16a) and multiple in the other forms (Figs.  3.12a, 3.13 and 3.14a), with restriction to sunexposed areas in actinic form and distributed along Blaschko lines in linear variant (due to a mosaicism) [1, 3, 9]. While an erythematous background is often visible in lighter phototypes (Fig.  3.12a), in dark skin patients, lesions often show a hyper- or hypopigmented appearance (Figs. 3.14a and 3.16a) [1, 3, 9].

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Fig. 3.12  Disseminated actinic porokeratosis (inflammatory lesions) in a Caucasian lady (a). Dermoscopy reveals a brownish keratotic collarette with a double free edge along with central erythema and some unfocused vessels (b)

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Fig. 3.13  Disseminated actinic porokeratosis (non-inflammatory lesions) in a Caucasian lady (a). Dermoscopic assessment shows a white keratotic collarette with a double free edge along with central white areas and linear/dotted/linear-curved vessels (b)

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Fig. 3.14  Disseminated actinic porokeratosis in an African man (a). The typical brownish keratotic collarette with a double free edge is evident on dermoscopy along with keratotic follicular plugs (b)

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Fig. 3.15  Porokeratosis of Mibelli of the forearm of an Indian man (a). Dermoscopy reveals a peripheral gray keratotic collarette with a double free edge which is barely detectable as there is also remarkable hyperkeratosis (b)

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Fig. 3.16  Porokeratosis of Mibelli of the dorsal aspect of the hand in an Indian girl (a). Dermoscopic examination shows the typical peripheral brownish keratotic collarette with a double free edge and a central white background (b)

3.3.3 Dermoscopy

3.4.2 Clinical Presentation

Dermoscopy is a key diagnostic tool in porokeratosis, especially in dark-skinned patients in whom the peripheral keratotic margin is not always easy to identify on clinical ground [1, 3, 6, 7, 10, 11]. The dermoscopic hallmark consists of a peripheral keratotic rim featuring a double free edge representing the cornoid lamella on histology (Figs. 3.12b, 3.13, 3.14, 3.15 and 3.16b) [1, 3, 6, 7, 10, 11]. Its color may be either white/gray or brown, with the latter being more frequently seen in darker phototypes [1, 3, 6, 7, 10, 11]. Additionally, several less specific findings may be observed in the center of the lesions, including white scales, dotted/ reticular vessels (especially fair skin), keratotic plugs, white or brown structureless areas, and brown dots (especially dark skin) (Figs. 3.12b, 3.13, 3.14, 3.15 and 3.16b) [1, 3, 6, 7, 10, 11].

It typically presents as 1–2 mm in diameter, skin-colored or hypopigmented (particularly in dark-skinned patients), asymptomatic, shiny papules (Figs.  3.17a, 3.18 and 3.19a) most commonly affecting the abdomen, chest, extremities, and genitalia (especially in men) [1, 3]. Koebner phenomenon with lesions arranged in a linear pattern is quite common in LN [1, 3]. Several less frequent clinicopathological ­subtypes have been described, such as actinic, linear, perforating, purpuric/hemorrhagic, and vesicular [1, 3].

3.4 Lichen Nitidus 3.4.1 Introduction Lichen nitidus (LN) is an inflammatory condition typified by a self-limiting course in a few years that has been supposed to be triggered by allergens causing epidermal and dermal antigen-presenting cells to activate a cell-mediated response [1, 3]. No racial predilection has been reported in the literature, despite the general impression of a greater involvement of dark-skinned patients compared to lighter phototypes [1, 3].

3.4.3 Dermoscopy The typical dermoscopic pattern of LN in both fair and dark skin consists of round, homogeneous, sharply demarcated, white areas (one for each papule) characteristically devoid of skin markings (Figs. 3.17b and 3.19b); an orange hue may also be seen in lighter phototypes (Fig. 3.18b) [1, 3, 4, 6, 7, 12]. From a dermoscopic-pathological correlation point of view, these areas correspond to the dense lymphohistiocytic inflammatory cell infiltrate located in close proximity to the thinned epidermis and enveloped by bordering elongated rete ridges (“claw clutching a ball” appearance), while the loss of skin markings would be the result of the epidermal-­ dermal junction flattening (due to the pressure by the underlying dermal inflammatory cell infiltrate) [1, 3, 4, 6, 7, 12]. Dermoscopy may also come in handy to show clinically unnoticeable linear arrangement of some lesions (“micro-­ Koebner phenomenon”) (Fig. 3.18b) [1, 3, 4, 6, 7, 12].

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Fig. 3.17  Lichen nitidus (hypopigmented papules) in a Caucasian girl (a). Dermoscopy displays round white areas devoid of skin markings (b)

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Fig. 3.18  Lichen nitidus (skin-colored papules) in a Caucasian girl (a). Round orange areas are evident on dermoscopic assessment; some of them are arranged in a linear pattern (“micro-Koebner phenomenon”) (b)

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Fig. 3.19  Lichen nitidus (hypopigmented papules) in an African boy (a). Dermoscopy reveals very well-demarcated round white areas devoid of skin markings (b)

3.5 Lichen Striatus 3.5.1 Introduction Lichen striatus (LS) is a self-limiting inflammatory condition of unknown etiology manifesting with lesions following Blaschko’s lines [3, 13]. Although it may occur at any age, it tends to be more common in children, with a spontaneous healing within 1 year, yet it may last longer [3, 13].

3.5.2 Clinical Presentation LS usually manifests as skin-colored, erythematous, or hypopigmented (especially in darker phototypes) small (1–3  mm) papules often coalescing into linear plaques following lines of Blaschko of an extremity or trunk (Figs. 3.20a and 3.21a) [3, 13]. Post-inflammatory hypopigmentation is quite frequent especially in dark-skinned patients and may

last for long time (Figs.  3.22a and 3.23a), yet post-­ inflammatory hyperpigmentation is more uncommon and visible nearly exclusively in skin of color (Fig. 3.24a) [3, 13]. Onychodystrophy may also be seen less commonly, and it is often limited to a single nail [3, 13].

3.5.3 Dermoscopy Dermoscopic features of LS significantly vary according to patient’s phototype [3, 14]. In detail, the main findings in fair skin are poorly specific and include vessels of mixed morphology (dotted and linear-irregular) and white scaling (Fig.  3.20b), though ill-defined white areas may also be seen in hypopigmented variants or post-inflammatory ­hypopigmentation (Fig. 3.22b) [3, 14]. On the other hand, whereas the abovementioned vascular structures may also be detected in skin of color (Fig. 3.21b), LS in darker phototypes is mainly typified by non-follicular, ill-defined,

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Fig. 3.20  Lichen striatus (papular erythematous lesions) in a Caucasian man (a). A mixed vascular pattern (dotted and linear vessels) is evident on dermoscopy (b)

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Fig. 3.21  Lichen striatus (papular hypopigmented lesions) in an Indian boy (a). Dermoscopic examination reveals white scales as well as dotted and linear vessels (magnification in the inset) (b)

structureless white areas often coalescing to form polycyclic structures, with or without white or brown scales and brown dots (Fig. 3.23b) [3, 14]. From a histological point of view, white areas would be related to epidermal acanthosis and/or inflammatory reduction of the melanin content, while white and brown scaling would correspond to hyperkeratosis (with melanin exfoliation for brown scales) [3, 14].

Of note, in very dark phototypes, white eccrine sweat gland openings surrounded by brown circles may be also visible in the abovementioned white areas as a result of the typical arrangement of the dense inflammatory infiltrate around the eccrine sweat glands and ducts (Fig.  3.24b) [3]. Additionally, brown network-like structures may also be seen in post-inflammatory hyperpigmented lesions (Fig. 3.24b) [3, 14].

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Fig. 3.22  Lichen striatus (hypopigmented post-inflammatory lesions) in a Caucasian girl (a). Ill-defined confluent white areas are seen on dermoscopy (b)

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Fig. 3.23  Lichen striatus (hypopigmented post-inflammatory lesions) in an Indian boy (a). Dermoscopy shows ill-defined confluent white areas with white scales and a few brown dots (b). (Courtesy of Balachandra Ankad, MD – Bagalkot, India)

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Fig. 3.24  Lichen striatus (hyperpigmented post-inflammatory lesions) in an African man (a). Dermoscopy displays brown network and brown circles around white eccrine sweat gland openings (b). (Courtesy of Ibrahima Traoré, MD – Conakry, Guinea)

3.6 Lichen Spinulosus 3.6.1 Introduction Lichen spinulosus is a follicular keratotic dermatoses most commonly seen in children, though it may also be encountered in adults [15, 16]. Albeit its precise etiopathogenesis is yet to be clear, some authors have speculated it might be an abnormal reaction pattern of follicles to various triggering factors, including among the others vitamin A deficiency, exposure to toxins, infections (e.g., HIV), and autoimmune diseases (e.g., Crohn’s disease) [15, 16].

3.6.2 Clinical Presentation It presents with follicular papules of 1–3  mm in diameter associated with thorny and hair-like spines that cluster into more or less symmetrical plaques (Figs.  3.25a and 3.26a) [15, 16]. Lesions are usually localized, though generalized forms have been reported; trunk, neck, acral areas, buttocks, abdomen, and extensor arms are among the most commonly involved areas [15, 16]. Lichen spinulosus is usually asymptomatic and aflegmasic, yet pruritus and erythema may be

observed [15, 16]. Of note, in darker phototypes, lesions are typically more keratotic, and erythema is not found (Fig. 3.26a). Evolutions are variable, with some cases showing self-resolution and others persisting for many years [16].

3.6.3 Dermoscopy Dermoscopic pattern of lichen spinulosus consists of equidistant follicular plugs surrounded by a white halo (Figs. 3.25b and 3.26b), histologically corresponding to follicular hyperkeratosis and perifollicular acanthosis; hairs are usually present [15]. Notably, the color of the plugs may vary based on the phototype, with white and brown hue being more commonly observed in fair and dark skin, respectively. This difference is due to the melanin exfoliation that is associated with follicular hyperkeratosis in dark-skinned patients [6]. Additionally, plugs tend to be more pronounced in skin of color because of the higher tendency to follicular reactions, whereas a perifollicular erythematous halo may unfrequently be found in lighter phototypes [6]. Lastly, perifollicular scaling (Fig. 3.25b) and coiled hairs may also sometimes be evident, though the latter finding is usually focal (and not diffuse as seen in keratosis pilaris) [15].

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Fig. 3.25  Lichen spinulosus in a Caucasian child (a). Dermoscopy reveals white follicular plugs surrounded by a white halo (b)

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Fig. 3.26  Lichen spinulosus in an African woman (a). Dermoscopic examination shows brownish follicular plugs with a white halo (b) (Courtesy of Rosana Buffon, MD – Vicenza, Italy)

3.7 Keratosis Pilaris 3.7.1 Introduction Keratosis pilaris is a common condition that has been related to filaggrin loss-of-function mutations, atopic dermatitis, and ichthyosis vulgaris; such a condition is seen in every skin type [17, 18].

3.7.2 Clinical Presentation It typically manifests as more or less diffuse follicular scaly papules that are usually asymptomatic (Figs.  3.27a and 3.28a) [17, 18]. The main anatomical sites involved include

the extensor surfaces of the proximal extremities, though involvement of the lower limbs or cheeks is not so rare [17, 18]. Lesions in light phototypes show a reddish hue (Fig.  3.27a), whereas they are brownish in skin of color (Fig. 3.28a).

3.7.3 Dermoscopy Dermoscopic examination of keratosis pilaris usually reveals coiled and twisted hairs which are surrounded/embedded by white scales [15]. Notably, a perifollicular erythematous halo is visible in fair-skinned patients, while a brownish halo (diffuse pigmentation or reticular pigmentation) is evident in skin of color [15]. Moreover, a few dotted vessels may also sometimes be observed around the follicles in lighter phototypes [15].

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Fig. 3.27  Keratosis pilaris in a Caucasian boy (a). Coiled hairs along with perifollicular white scaling surrounded by an erythematous halo are evident on dermoscopy (b)

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Fig. 3.28  Keratosis pilaris in an African woman (a). Dermoscopy displays coiled and twisted hairs embedded by white scaling along with a brown reticular perifollicular pigmentation (b)

References 1. Lallas A, Errichetti E.  Papulosquamous disorders. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 2–46. 2. Wang A, Pandya AG. Pityriasis Lichenoides Chronica. In: Jackson-­ Richards D, Pandya AG, editors. Dermatology atlas for skin of color. 1st ed. Berlin: Springer; 2014. p. 127–30. 3. Errichetti E, Ankad B, Neema S, et al. Papulosquamous disorders. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2021. p. 3–28.

4. Errichetti E.  Dermoscopy of inflammatory dermatoses (inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80. 5. Errichetti E, Lacarrubba F, Micali G, Piccirillo A, Stinco G.  Differentiation of pityriasis lichenoides chronica from guttate psoriasis by dermoscopy. Clin Exp Dermatol. 2015;40:804–6. 6. Errichetti E, Ankad BS, Jha AK, et al. International Dermoscopy Society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 7. Errichetti E, Ankad BS, Sonthalia S, et  al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a

44 comparative retrospective study by the International Dermoscopy Society. Eur J Dermatol. 2020;30:688–98. 8. Jacyk WK. Pityriasis rubra pilaris in black south Africans. Clin Exp Dermatol. 1999;24:160–3. 9. LeCourt AP.  Porokeratosis. Emedicinemedscapecom. 2022. Accessed 16 June 2022. 10. Errichetti E, Francesco V, Pegolo E, Stinco G.  Dermoscopy in assisting the diagnosis of linear porokeratosis. J Dermatol. 2017;44:e248–9. 11. Zaar O, Polesie S, Navarrete-Dechent C, et  al. Dermoscopy of porokeratosis: results from a multicentre study of the International Dermoscopy Society. J Eur Acad Dermatol Venereol. 2021;35:2091–6. 12. Errichetti E, Stinco G.  Comment on “Dermatoscopic features of lichen nitidus”. Pediatr Dermatol. 2018;35:879–80. 13. Condie D, Pandya AG.  Lichen planus, Nitidus, and Striatus. In: Jackson-Richards D, Pandya AG, editors. Dermatology atlas for skin of color. 1st ed. Berlin: Springer; 2014. p. 115–22.

E. Errichetti et al. 14. Appendix VIII.  In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 325–7. 15. Beergouder SL, Rajput CD, Koti VR.  Miscellaneous conditions. In: Ankad BS, Mukherjee SS, Nikam BP, editors. Dermoscopy histopathology correlation. 1st ed. Singapore: Springer; 2021. p. 391–419. 16. Sahni VN, Dao DP, Sahni DR, Secrest AM.  Lichen spinulosus: insights into treatment. Dermatol Online J. 2021;27:10. 17. Bayazit S, Aşkın Ö, Kutlubay Z.  Comparative study of the efficacy of fractional Er: YAG 2940  nm laser and Q-switched Nd: YAG 1064  nm laser in keratosis pilaris. J Cosmet Dermatol. 2022;21:3809–13. https://doi.org/10.1111/jocd.15193. 18. Salava A, Salo V, Remitz A. Keratosis pilaris and filaggrin loss-of-­ function mutations in patients with atopic dermatitis—results of a Finnish cross-sectional study. J Dermatol. 2022;49:928–32. https:// doi.org/10.1111/1346-­8138.16477.

4

Other Papulonodular Disorders Enzo Errichetti

Contents 4.1 4.1.1  4.1.2  4.1.3 

Papular Acantholytic Dermatoses  Introduction  Clinical Presentation  Dermoscopy 

 45  45  45  46

4.2 4.2.1  4.2.2  4.2.3 

Papular Urticaria  Introduction  Clinical Presentation  Dermoscopy 

 50  50  50  50

4.3 4.3.1  4.3.2  4.3.3 

Prurigo Nodularis  Introduction  Clinical Presentation  Dermoscopy 

 51  51  51  51

4.4 4.4.1  4.4.2  4.4.3 

 cquired Perforating Dermatoses  A Introduction  Clinical Presentation  Dermoscopy 

 53  53  53  53

References 

 56

4.1 Papular Acantholytic Dermatoses

4.1.2 Clinical Presentation

4.1.1 Introduction

Both Darier’s disease and Grover’s disease are typified by itchy or asymptomatic papules involving seborrheic areas, skin creases, and trunk (Figs. 4.1a, 4.2 and 4.3a) in the former and central back/mid-chest in the latter (Figs. 4.4a, 4.5, 4.6 and 4.7a) [1, 2]. Unlike Grover’s disease, in which lesions are usually discrete (Figs. 4.4a, 4.5, 4.6 and 4.7a), papules of Darier’s disease often coalesce to form plaques (Figs. 4.1a and 4.2a), especially in the folds, where lesions display a macerated/eroded surface [1, 2]. Additionally, Darier’s dis-

Darier’s disease and Grover’s disease are the main papular acantholytic dermatoses, with the latter being sporadic and the former inherited with autosomal dominant pattern due to mutations in the gene ATP2A2 (encoding an intracellular calcium pump) [1, 2]. Whereas Darier’s disease tends to arise in the first two decades of life, Grover’s disease typically occurs in people over 50 years of age [1, 2].

E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_4

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Fig. 4.1  Darier’s disease in a Caucasian woman (a). Dermoscopy reveals a yellow star-like structure with a white halo and peripheral vessels (b)

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Fig. 4.2  Darier’s disease in an Indian man (a). Dermoscopic assessment displays brownish polygonal and star-like structures surrounded by a greyish halo (b). (Courtesy of Biswanath Behera, MD – Bhubaneswar, India)

ease is typically associated with nail abnormalities, mucous membrane changes, and acral skin lesions (palmar pits and discrete, symmetric, flat-topped, skin-colored papules on the dorsal aspects of hands and foot, similar to lesions seen in acrokeratosis verruciformis of Hopf—Figs. 4.8a and 4.9a) [1, 2]. The main difference between fair and dark skin is the diverse color of the papules, with lighter and darker phototypes, respectively, displaying a reddish and brown hue, and the higher prevalence of post-inflammatory hypo- and hyperpigmentation in skin of color (Fig. 4.3a) [1, 2].

4.1.3 Dermoscopy The dermoscopic hallmark of Darier’s disease consists of a central polygonal or star-like area (displaying a yellow-­ orange and brown shade in lighter and darker phototypes, respectively) surrounded by a white halo (Figs. 4.1b, 4.2 and 4.3b) [1–8]. Histologically, the central yellow-orange/brown area corresponds to a compact keratotic mass mixed with serum (resulting from exudation due to acantholysis) and melanin (in skin of color), while the peripheral white halo is

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Fig. 4.3  Darier’s disease in an African American woman (a). Dermoscopic examination shows red-brownish star-like structures surrounded by a grayish halo as well as polygonal/star-like white areas (b). (Courtesy of Richard Usatine, MD – San Antonio, USA)

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Fig. 4.4  Grover’s disease (Darier-like histological subtype) in a Caucasian woman (a). Dermoscopic assessment displays an orange star-like structure with a white halo (b)

linked to epidermal acanthosis [1–8]. Notably, a perilesional gray-brown pigmentation and star-shaped or polygonal white areas in healed skin are often seen in dark-skinned patients as a result of post-inflammatory hyper- and hypopigmentation, respectively (Fig. 4.3b) [2]. Star-like/linear and parallel erosions over a white background (with or without white shiny lines) may be observed in lesions involving the creases in both fair and dark skin [1–6]. With regard to Grover’s disease, its dermoscopic pattern varies based on histological subtype, with Darier-like variant featuring similar findings as Darier’s disease (central polygonal/star-like yellow-orange/ brown area with a white halo) (Figs.  4.4b and 4.5b) and

spongiotic variant showing only unspecific features, including white or brown (dark skin) scales and subtle dilated vessels (especially in fair skin) (Figs. 4.6b and 4.7b) [1, 2, 7]. Finally, acral papules of the dorsal aspect of hands and foot seen in both Darier’s disease and acrokeratosis verruciformis of Hopf feature a homogeneous white background with loss of physiological skin creases regardless skin type (Figs. 4.8b and 4.9b), yet further findings may be observed in dark phototypes, mainly including brown dots radially arranged or creating a cobblestone appearance (Fig. 4.9b) but also white lines/network, whitish-yellowish septae, desquamation, and dotted vessels within reticulation [9].

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Fig. 4.5  Grover’s disease (spongiotic histological subtype) in a Caucasian woman (a). White scales, orange background, and dilated vessels are evident on dermoscopy (b)

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Fig. 4.6  Grover’s disease (spongiotic histological subtype) in an Indian man (a). Middle Eastern man (a). Dermoscopy reveals white/brown scales/crusts with a peripheral brown halo (b). (Courtesy of Balachandra S. Ankad, MD – Bagalkot, India)

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Fig. 4.7  Grover’s disease (spongiotic histological subtype) in a Caucasian woman (a). Dermoscopic assessment displays brown star-like structures with a gray halo surrounded by a brown rim (b). (Courtesy of Bengü Nisa Akay, MD – Ankara, Turkey)

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Fig. 4.8  Acrokeratosis verruciformis of Hopf in a Caucasian man (a). A homogeneous white background devoid of skin creases is evident on dermoscopy (b)

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Fig. 4.9  Acrokeratosis verruciformis of Hopf in an Indian man (a). Dermoscopy reveals a homogeneous white background containing brown dots (b) (Courtesy of Biswanath Behera, MD – Bhubaneswar, India)

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4.2 Papular Urticaria 4.2.1 Introduction Papular urticaria (PU) is a common dermatosis mainly affecting children that results from a hypersensitivity reaction to the bites of several insects, such as mosquitoes, sandflies, fleas, and bedbugs [1, 2].

4.2.2 Clinical Presentation PU presents as recurrent crops of pruritic erythematous (fair skin) or skin-colored (dark skin) papules and papulovesicles classically distributed in an asymmetrical pattern over exposed areas of the body (Figs. 4.10a, 4.11 and 4.12a), yet a

covered areas may also be affected [1, 2]. Single or multiple erosions, ulcerations, and crusts may result from scratching or secondary infection [1, 2]. Of note, post-inflammatory hypo- or hyperpigmented macules and/or patches may be observed in darker phototypes [2].

4.2.3 Dermoscopy The main dermoscopic features of PU include a central crust or hemorrhagic punctum reflecting the site of the insect bite (Figs.  4.10b, 4.11 and 4.12b) or hemorrhagic spots due to dermal extravasated erythrocytes (Fig. 4.11b) [1, 2]. Notably, hemorrhagic structures are more difficult to see in very dark skin phototypes [1, 2]. Further dermoscopic findings are erosions, roundish or angulated brown/yellow crusts, and white

b

Fig. 4.10  Papular urticaria in a Caucasian woman due to pyemotes ventricosus (“comet-like” appearance) (a). Dermoscopic examination shows a central crust (arrowhead) with multiple hemorrhagic dots/spots (b)

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b

Fig. 4.11  Papular urticaria in a Caucasian man (a). Dermoscopic examination shows a central hemorrhagic punctum (arrowhead) (b)

4  Other Papulonodular Disorders

a

51

b

Fig. 4.12  Papular urticaria in a North African boy (a). A central crust is visible on dermoscopy (b)

structureless areas (healing lesions), with the last feature being more commonly observed in dark-skinned patients as a result of post-inflammatory hypopigmentation [2].

4.17a) [1, 2]. Moreover, post-inflammatory hyper- or hypopigmentation is frequently seen in darker phototypes [1, 2].

4.3 Prurigo Nodularis

4.3.3 Dermoscopy

4.3.1 Introduction

PN in both fair and dark skin typically displays the so-called “white starburst” pattern, which is characterized by peripheral, radial, white striae over a reddish (especially in fair skin) or brownish (especially in dark skin) (Figs. 4.13b and 4.15b) background [1, 2, 8, 10]. White peripheral scaling collarette with an inner free edge may be visible at the periphery, whereas ulceration/erosion, crusting, white hyperkeratosis/scales, broken hairs, follicular plugs, white structureless areas/globules, hemorrhagic dots/globules, and/or dotted/globular vessels (often surrounded by a white halo) may be evident in the center of the lesions (Figs. 4.13b, 4.14, 4.15, 4.16 and 4.17b) [1, 2, 8, 10]. From a dermoscopic-­ pathological correlation point of view, white striae are related to vertically arranged thickened collagen fibers in papillary dermis, while red and brown background results from dermal inflammation and basal cell layer hyperpigmentation, respectively [1, 2, 8, 10]. Notably, dermoscopy may also facilitate retrospective diagnosis of PN since healing/non-­ active lesions often retain the abovementioned “white starburst” pattern [1, 2, 8, 10].

Prurigo nodularis (PN) is a chronic dermatosis resulting from skin picking and scratching [1, 2]. It is by far more common in dark-skinned patients compared to fair-skinned patients and mainly involves middle-aged and elderly people, though it may occur at any age [1, 2]. Atopic diathesis is often found in patients suffering from PN, yet systemic causes of pruritus may also be associated with this condition [1, 2].

4.3.2 Clinical Presentation PN presents as discrete hyperkeratotic or excoriated nodules often arranged in a linear or grouped pattern that mainly affect extensor surfaces of the arms, legs, and trunk with sparing of palms, soles, face, and center of the back (“butterfly sign”) (Figs. 4.13a, 4.14, 4.15, 4.16 and 4.17a) [1, 2]. Color of the nodules is pink-red in fair skin (Figs. 4.13a and 4.17a) and brownish in dark skin (Figs.  4.15a, 4.16 and

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a

b

Fig. 4.13  Prurigo nodularis in a Caucasian man (a). A bright white area with peripheral radial striae (“white starburst” pattern) is evident on dermoscopic examination (b)

a

b

Fig. 4.14  Prurigo nodularis (excoriated lesions) in a Caucasian man (a). Dermoscopy reveals white follicular plugs surrounded by dotted vessels having a white halo; multiple hemorrhagic dots/spots and peripheral white halo are also seen (b)

Fig. 4.15  Prurigo nodularis in an African man (a). Dermoscopic assessment displays the typical “white starburst” pattern (bright white area with peripheral radial projections) with a peripheral brown halo (b)

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Fig. 4.16  Prurigo nodularis in an African man (a). Several dotted vessels showing white halo over a brown background along with broken hair (arrowhead) are evident on dermoscopy (b)

Fig. 4.17  Prurigo nodularis (excoriated lesions) in an African boy (a). Dermoscopy shows peripheral radial white projections and white collarette scaling as well as uniform dotted vessels surrounded by a white halo, sparse brown dots, and a few white follicular plugs in the center (b)

4.4 Acquired Perforating Dermatoses

4.4.2 Clinical Presentation

4.4.1 Introduction

APD are clinically characterized by itchy, round, umbilicated, skin-colored (fair skin), or hyperpigmented (dark skin) papules and nodules with a crust or keratotic plug in the center; extensor surfaces of the extremities and the trunk are the most commonly involved sites (Figs. 4.18a, 4.19, 4.20, 4.21, 4.22 and 4.23a) [1, 2, 11].

“Acquired perforating dermatoses” (APD) is the term used to refer to a group of disorders histologically typified by invagination of the epidermis (either follicular or perifollicular) along with extrusion of dermal material, whose composition differs based on the subtype (i.e., collagen bundles in acquired reactive perforating collagenosis [ARPC], elastic fibers in acquired elastosis perforans serpiginosa [AEPS], amorphous dermal material, and/or keratin in Kyrle’s disease [KD] and degenerating collagen and extracellular matrix in perforating folliculitis [PF]—overlaps may be possible) [1, 2, 11]. Chronic renal disease and diabetes mellitus are the most common associated conditions [1, 2, 11].

4.4.3 Dermoscopy ARPC and PF share a similar dermoscopic aspect, the so-­ called “trizonal concentric” pattern (Figs.  4.18b, 4.19b, 4.21b and 4.22b), which is typified by the presence of three concentric areas, with a central white/yellow/brown-

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Fig. 4.18  Acquired reactive perforating collagenosis in a Caucasian woman (a). The typical “trizonal concentric” pattern is evident on dermoscopy with three concentric areas [central brown structureless area

E. Errichetti

(I) surrounded by a white keratotic collarette (II) and an erythematous halo (III)] (b)

Fig. 4.19  Perforating folliculitis in a Caucasian woman (a). Dermoscopic examination reveals a central brown structureless area surrounded by a white keratotic collarette and an erythematous halo (“trizonal concentric” pattern) (b)

gray structureless area/keratotic plug (I) surrounded by a white keratotic collarette (II) and an erythematous (fair skin) or white/gray (dark skin) halo (III) [1–4, 8]. In lighter phototypes, dotted vessels may be seen at the periphery, whereas a peripheral brown halo (either homogeneous or reticular) is often evident in skin of color, thus configuring a pattern with four concentric areas (Figs. 4.21b and 4.22b) [1–4, 8]. On the other hand, KD in fair-skinned patients has been described to show central whitish-brownish scales surrounded by a structureless whitish-gray area and a peripheral, brown, delicate pig-

mentation (Fig.  4.20b) [1, 2]. In skin of color, dermoscopic pattern of KD is similar, though the peripheral pigmentation is typically more marked (Fig.  4.23b). Dermoscopy of AEPS has been described only in Caucasian patients, with a pattern being characterized by central whitish structureless area with a crown of arborizing vessels or central pink-­ yellow discoloration with peripheral brownish crusted papules surrounded by a white halo and configuring an “archipelago”-like appearance [1–4, 12].

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Fig. 4.20  Kyrle’s disease in a Caucasian man (a). Dermoscopy shows central whitish-brownish scales surrounded by a structureless whitish-gray area and a peripheral, brown, delicate pigmentation (b)

a

Fig. 4.21  Acquired reactive perforating collagenosis in an Indian woman (a). Dermoscopic pattern is similar as the one seen in light phototypes, with three concentric areas, i.e., central brown-gray structure-

a

Fig. 4.22  Perforating folliculitis in an Indian woman (a). Dermoscopic assessment displays a central white keratotic plug surrounded by a white keratotic collarette and a grey halo (arrowhead); a peripheral

b

less area (I) surrounded by a white keratotic collarette (II) and a gray halo (III); additionally, a perilesional reticular pigmentation is also evident (b). (Courtesy of Biswanath Behera, MD – Bhubaneswar, India)

b

brown pigmentation is also evident, thus configuring a pattern with four concentric areas (b). (Courtesy of Balachandra S.  Ankad, MD  – Bagalkot, India)

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b

Fig. 4.23  Kyrle’s disease in an Indian man (a). Dermoscopy reveals central brownish crusting surrounded by a structureless whitish-gray area and a peripheral dark brown pigmentation (b). (Courtesy of Balachandra S. Ankad, MD – Bagalkot, India)

References 1. Errichetti E, Lallas A, Ioannides D. Other papulonodular disorders. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 47–55. 2. Errichetti E, Ankad B, Akay BN, Usatine R, Lallas A. Other papulosquamous disorders. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 29–34. 3. Errichetti E.  Dermoscopy of inflammatory dermatoses (inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80. 4. Errichetti E, Stinco G. Dermoscopy in general dermatology: a practical overview. Dermatol Ther (Heidelb). 2016;6:471–507. 5. Errichetti E, Stinco G, Lacarrubba F, Micali G.  Dermoscopy of Darier’s disease. J Eur Acad Dermatol Venereol. 2016;30:1392–4. 6. Lacarrubba F, Verzì AE, Errichetti E, Stinco G, Micali G.  Darier disease: dermoscopy, confocal microscopy, and histologic correlations. J Am Acad Dermatol. 2015;73:e97–9.

7. Errichetti E, De Francesco V, Pegolo E, Stinco G. Dermoscopy of Grover’s disease: variability according to histological subtype. J Dermatol. 2016;43:937–9. 8. Errichetti E, Ankad BS, Sonthalia S, et  al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the International Dermoscopy Society. Eur J Dermatol. 2020;30:688–98. 9. Errichetti E.  Acrokeratosis verruciformis of Hopf: dermoscopic approach in lighter phototypes. J Eur Acad Dermatol Venereol. 2022;37:e427–8. https://doi.org/10.1111/jdv.18485. 10. Errichetti E, Piccirillo A, Stinco G. Dermoscopy of prurigo nodularis. J Dermatol. 2015;42:632–4. 11. Ramirez-Fort MK, Khan F, Rosendahl CO, Mercer SE, Shim-­ Chang H, Levitt JO.  Acquired perforating dermatosis: a clinical and dermatoscopic correlation. Dermatol Online J. 2013;19:18958. 12. Navarrete-Dechent C, Puerto C, Bajaj S, Marghoob AA, González S, Jaque A. Dermoscopy of elastosis perforans serpiginosa: a useful tool to distinguish it from granuloma annulare. J Am Acad Dermatol. 2015;73:e7–9.

5

Noninfectious Granulomatous Disorders Enzo Errichetti

Contents 5.1 5.1.1  5.1.2  5.1.3 

Sarcoidosis  Introduction  Clinical Presentation  Dermoscopy 

 57  57  58  58

5.2 5.2.1  5.2.2  5.2.3 

Necrobiosis Lipoidica  Introduction  Clinical Presentation  Dermoscopy 

 60  60  60  60

5.3 5.3.1  5.3.2  5.3.3 

Granuloma Annulare  Introduction  Clinical Presentation  Dermoscopy 

 61  61  61  61

5.4 5.4.1  5.4.2  5.4.3 

 nnular Elastolytic Giant Cell Granuloma  A Introduction  Clinical Presentation  Dermoscopy 

 63  63  63  63

5.5 5.5.1  5.5.2  5.5.3 

 oreign Body Granuloma  F Introduction  Clinical Presentation  Dermoscopy 

 64  64  64  64

5.6 5.6.1  5.6.2  5.6.3 

 upus Miliaris Disseminatus Faciei  L Introduction  Clinical Presentation  Dermoscopy 

 65  65  65  65

References 

5.1 Sarcoidosis 5.1.1 Introduction Sarcoidosis is a multisystem granulomatous disease which is characterized by noncaseating epithelioid granulomas with few surrounding lymphocytes (“naked” granulomas)

 66

on histology [1, 2]. Although it may affect almost any organ system, lungs, skin, eyes, and lymph nodes are the most commonly involved sites [1, 2]. African Americans and Northern Europeans are the two groups reported to be affected most frequently, with a tendency to involve people between 20 and 40  years of age and females more than males [1, 2].

E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_5

57

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5.1.2 Clinical Presentation Skin involvement in sarcoidosis may significantly vary from a clinical point of view, with two groups of manifestations being recognized, including nonspecific/reactive (e.g., erythema nodosum) and specific (typified by “naked” granulomas from a histological point of view) lesions [1, 2]. Regarding the latter, they are typically asymptomatic and display variable morphologies, such as papules, nodules, patches, and/or plaques (Figs. 5.1a, 5.2, 5.3 and 5.4a); lesions surface may be smooth, atrophic, scaly, hyperkeratotic, or ulcerated [1, 2]. Face, neck, upper back, and extremities are the most common involved sites, yet it may affect other anatomical areas [1, 2]. Color of the lesions may differ based on the phototype, with a red-violaceous

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and violaceous-brown/yellow-brown being more common in fair- and dark-skinned patients (Figs. 5.1a, 5.2, 5.3 and 5.4a) [1, 2]. Finally, several less frequent clinical subtypes do exist, including subcutaneous sarcoidosis, ichthyosislike sarcoidosis, lichenoid sarcoidosis, scar sarcoidosis, lupus pernio and hypopigmented sarcoidosis, with the last two variants being more commonly encountered in darker phototypes [1, 2].

5.1.3 Dermoscopy The main dermoscopic clue of all clinical variants of cutaneous sarcoidosis is represented by the presence of either focal or diffuse orange structureless areas histologically related to a

b

Fig. 5.1  Plaque-type sarcoidosis of the face in a Caucasian man (a). Dermoscopy shows a diffuse structureless orange areas (background) along with focused linear vessels with branches (b)

a

b

Fig. 5.2  Plaque-type sarcoidosis of the abdomen in a Caucasian woman (a). Focal structureless orange areas and several focused linear-curved vessels are evident on dermoscopic examination (b)

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dense and compact granulomatous infiltrate in the dermis (“mass effect”) [1–7]. Importantly, while such areas are wellvisible in fair-skinned patients (Figs. 5.1b and 5.2b), they are often more subtle and feature a yellowish shade in skin of color as a result of the darker background (Figs. 5.3b and 5.4b) [2, 6]. Applying a slight pressure on the skin may, however, enhance their visualization, thanks to the reduction of erythema [1–6]. Another typical dermoscopic feature of sarcoidosis includes vascular structures (most commonly showing a linear-branching morphology) which usually appear sharply

a

b

Fig. 5.3  Papular-type sarcoidosis of the neck in an African woman (a). Dermoscopic assessment displays diffuse structureless yellow areas (background) as well as multiple bright white structureless areas and

a

demarcated as granulomas displace the dermal vessels upward (closer to the skin surface), thus looking more focused [1–6]. Of note, albeit vessels may sometimes be seen in darker phototype (Figs. 5.3b and 5.4b), they are by far more common in fair skin (Figs. 5.1b and 5.2b) [1–6]. Finally, further less specific dermoscopic findings include white scales, focal white structureless areas, follicular plugs, white globules or lines, and focal brown network or structureless areas, with these last features being more frequent in skin of color (Figs. 5.3b and 5.4b) [2, 6].

peripheral brown network (b). (Courtesy of Nkechi A.  Enechukwu, MD – Awka, Nigeria)

b

Fig. 5.4  Plaque-type sarcoidosis of the thigh in an African woman (a). Dermoscopy shows multiple yellow structureless areas, white scales, few focused linear vessels (arrowhead), and peripheral brown network-like structures (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

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5.2 Necrobiosis Lipoidica

5.2.3 Dermoscopy

5.2.1 Introduction

The main dermoscopic clues of NL in both fair and dark skin are usually visible in the center of the lesions and include structureless yellowish-orangish areas, histologically related to dermal granulomas and lipid deposits (responsible for the yellow color, which is typically absent in other granulomatous dermatoses), along with vessels featuring a variable morphology based on lesions stage (Figs. 5.5b and 5.6b) [1–7]. In particular, dotted, globular, comma-shaped, and glomerular vessels are the most frequent shapes in early phases, while reticular, linear, and hairpin-like vessels are more commonly seen in mature lesions and branching-­serpentine vessels (showing a diameter that decreases from the center to the periphery of the lesion) in advanced stages (Figs. 5.5b and 5.6b) [1–7]. Importantly, vascular structures in NL are usually in-focus due to the epidermal atrophy that makes the vessels closer to the skin surface, thus appearing sharper (Figs. 5.5b and 5.6b) [1–7]. Notably, whereas vessels in well-established lesions are generally visible also in skin of color, they may be difficult to be seen in early phases [1–7]. Another relevant difference according to skin color ­background is that darker phototypes more commonly display brown structureless or reticular areas in the center and/or at the periphery of the lesions (Fig. 5.6b) [1–7]. Finally, further less common findings visible regardless skin type include ulcerations, crusting, white scaling, and fibrotic white structureless areas (particularly in long-standing lesions) [1–7].

Necrobiosis lipoidica (NL) is a chronic idiopathic granulomatous disorder histologically typified by necrobiotic degeneration of dermal collagen which most commonly involves young and middle-aged adults with a higher prevalence in the female gender [1, 2]. Diabetes and thyroid dysfunction have been reported as possible systemic associations but only in a minority of instances [1, 2]. NL is typically more common in Caucasians compared to people with skin of color [1, 2].

5.2.2 Clinical Presentation Clinically, NL initially manifests with asymptomatic reddish (fair skin) or brown (dark skin) firm papules that gradually increase in size to form plaques showing red/brown margins and a waxy yellow-brown atrophic center often showing prominent telangiectasias (especially in skin of color) and/or ulcerations (Figs. 5.5a and 5.6a); altered sensations and partial alopecia may be seen in lesional areas [1, 2]. Pretibial areas (with a unilateral or bilateral distribution pattern) are the most commonly affected sites, yet other areas may also be involved, such as scalp, upper extremities, and face [1, 2].

a

b

Fig. 5.5  Necrobiosis lipoidica in a Caucasian woman (a). Dermoscopic examination displays multiple focal structureless yellow and white areas along with focused linear-serpiginous vessels whose diameter decreases toward the periphery of the lesion (b)

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b

Fig. 5.6  Necrobiosis lipoidica of the leg in an Indian woman (a). Dermoscopy: focused branching serpiginous vessels whose diameter reduces toward the periphery (better seen in the inset) and brown areas;

faint structureless yellowish areas are also present (b). (Adapted from “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

5.3 Granuloma Annulare

exist, such as subcutaneous, perforating, and patch-type subtype [1, 2].

5.3.1 Introduction Granuloma annulare (GA) is thought to be a clinicopathological reactive condition resulting from a hypersensitivity reaction to a dermal component triggered by several factors, such as skin infections, infestations, or trauma, yet no clear triggers may be identified in most cases [1, 2]. Four main histological subtypes are recognized, including “interstitial,” “palisading granuloma,” sarcoidosis-like, and mixed, with the first two variants being the most frequent [1, 2].

5.3.2 Clinical Presentation GA usually presents as localized or generalized, asymptomatic, non-scaly papules/nodules that are sparse or confluent to form annular or roundish plaques (Figs. 5.7a, 5.8, 5.9 and 5.10a) [1, 2]. Lesions shade is usually pinkish, red, or violaceous in fair skin and violaceous or light to dark brown in dark skin (Figs. 5.7a, 5.8, 5.9 and 5.10a) [1, 2]. Several less frequent clinicopathological forms do

5.3.3 Dermoscopy Focal/diffuse orange structureless areas, focal/diffuse white structureless areas, erythema, and sparse dotted or linear/linear curved vessels are the most frequent dermoscopic features of GA (Figs.  5.7b, 5.9 and 5.10b) [1–8]. Notably, orange areas are usually evident only in “palisading granuloma” histological subtype as they result from the presence of a compact granulomatous infiltrate in the dermis (Fig. 5.7b), while the other dermoscopic findings are independent from the histological variant [1, 8]. Importantly, unlike sarcoidosis, vessels in GA are typically unfocused and subtle (Figs. 5.7b and 5.8b), thus being quite difficult to see in skin of color (Figs.  5.9b and 5.10b) [1, 2, 6]. Additionally, orange areas in darker phototypes often show a yellowish hue due to the brown background and are more easily detected in the skin creases where skin is thinner (Fig.  5.9b); brown structureless and/or network-like areas and/or network may also be seen in these patients (Figs. 5.9b and 5.10b) [1, 2, 6].

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a

b

Fig. 5.7  Granuloma annulare (palisading histological variant) in a Caucasian woman (a). Dermoscopy reveals multiple focal structureless white and orange areas as well as unfocused vessels of variable morphology, including dotted, linear, and linear with short branches (b)

a

b

Fig. 5.8  Granuloma annulare (interstitial histological variant) in a Caucasian woman (a). A reddish background with several focal white structureless areas and some unfocused vessels of mixed shapes are seen on dermoscopy (b)

a

Fig. 5.9  Granuloma annulare (palisading histological variant) in a North African man (a). The main dermoscopic clues are multifocal structureless white areas and yellow areas that are better seen in the skin

b

creases (magnification in the inset—arrowhead); brown pigmentary structures are also evident (b)

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b

Fig. 5.10  Granuloma annulare (interstitial histological variant) in an Indian man (a). Dermoscopy displays multifocal structureless white areas (arrowheads) along with multiple brown structureless areas (b)

5.4 Annular Elastolytic Giant Cell Granuloma 5.4.1 Introduction Annular elastolytic giant cell granuloma (AEGCG) is an uncommon granulomatous dermatosis histologically typified by loss of elastic fibers and elastophagocytosis by multinucleated giant cells [1, 2, 9]. Ultraviolet rays, heat, or other unknown factors are thought to trigger a cellular immune response toward elastic fibers [1, 2, 9].

5.4.2 Clinical Presentation From a clinical point of view, AEGCG manifests as small reddish (especially in fair skin) or brownish (especially in dark skin) papules progressing to annular/serpiginous plaques having with raised borders and, often, an hypopigmented or atrophic center (Figs. 5.11a and 5.12a) [1, 2, 9]. Sun-exposed areas are the most frequently involved sites, yet it may also affect sun-protected areas [1, 2, 9].

5.4.3 Dermoscopy Dermoscopic examination of AEGCG in fair skin typically reveals an orange structureless area along with white-gray scaling over the active margin, whereas homogeneous, reticular, sharp vessels on a pale pinkish background are commonly seen in the center of the lesion (Fig. 5.11b) [1–3, 9, 10]. From a dermoscopic-pathological correlation point of view, orange areas, scaling, and reticular vessels are related to dermal granulomas, hyperkeratosis, and subpapillary vascular plexus dilatation associated with epidermal atrophy (which makes vessels closer to skin surface, thus appearing sharp) [1–3, 9, 10]. Of note, although orange areas and reticular vessels have also been reported in skin of color, they are usually more subtle and difficult to appreciate (Fig. 5.12b) [10]. Additionally, in darker phototypes, it is also possible to see white as well as brown structureless areas (Fig. 5.12b) [10].

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a

b

Fig. 5.11  Annular elastolytic giant cell granuloma in a Caucasian woman (a). Dermoscopy shows peripheral orange structureless areas with central focused reticular vessels (b)

a

b

Fig. 5.12  Annular elastolytic giant cell granuloma in an Indian woman (a). In dark-skinned patients, dermoscopic examination may be quite unspecific with no orange peripheral structures and central reticular

vessels; in this case, only peripheral erythema and central brown areas are seen (b)

5.5 Foreign Body Granuloma

brownish in skin of color (authors’ personal experience) (Figs. 5.13a and 5.14a) [11].

5.5.1 Introduction Foreign body granuloma (FBG) is a form of chronic inflammatory response to various agents histologically typified by granulomas with a necrotic center surrounded by macrophages, epithelioid cells, and fibrous tissue [11].

5.5.3 Dermoscopy

FBG may display a heterogeneous dermoscopic presentation, with main features being reddish or bluish structureless areas and white fibrotic areas; other findings include rainbow pattern, orange areas, polymorphic vessels (either blurred or in-focus), 5.5.2 Clinical Presentation erosions, scales, and hyperkeratosis (authors’ personal experience) (Figs. 5.13b and 5.14b) [11]. Although dermoscopic patFrom a clinical point of view, FBG usually manifests as a tern of FBG is generally independent from phototype, fibrotic solitary or multiple infiltrated papules or nodules, whose white areas and hyperkeratosis tend to be more marked in skin shade vary from pink-reddish in light phototypes to red-­ of color (authors’ personal experience) (Figs. 5.14b) [11].

5  Noninfectious Granulomatous Disorders

a

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b

Fig. 5.13  Foreign body granuloma of the face in a Caucasian woman (a). Dermoscopic assessment reveals multiple structureless orange and white areas along with linear vessels (arrowhead), crusting, and hemorrhagic areas (b). (Courtesy of Arturo Galvan, MD – Verona, Italy)

a

b

Fig. 5.14  Foreign body granuloma of the ear in an Indian woman (a). Multiple bright white areas and peripheral brown pigmentation are the main dermoscopic clues (b). (Courtesy of Balachandra S. Ankad, MD – Bagalkot, India)

5.6 Lupus Miliaris Disseminatus Faciei 5.6.1 Introduction Lupus miliaris disseminatus faciei (LMDF), also referred to as acne agminata, is a relatively uncommon granulomatous condition thought to be related to an inflammatory reaction to destroyed hair follicles [1–3, 10].

5.6.2 Clinical Presentation LMDF manifests as red-brown (fair skin) or yellowish-red to brown (dark skin) papules that tend to aggregate in groups and involve the central areas of the face, such as periocular areas, cheeks, and nose (Figs. 5.15a and 5.16a)

[1–3, 10]. Lesions tend to heal over a period of 1–2 years, sometimes leaving scars, especially in darker phototypes [1–3, 10].

5.6.3 Dermoscopy Dermoscopy of LMDF shows orange (fair skin) or orange-­ yellow (dark skin) structureless areas characteristically distributed around follicular keratotic plugs which histologically reflect dermal granulomas around follicles filled with keratotic material (follicular hyperkeratosis) (Figs.  5.15b and 5.16b) [1–3, 10]. Additionally, diffuse scales, erythema, and vessels may also be present, with the last two findings being more common in lighter phototypes [1–3, 10].

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a

b

Fig. 5.15  Lupus miliaris disseminatus faciei in a Caucasian woman (a). Dermoscopy displays follicular white plugs surrounded by orange areas; some linear and dotted vessels are also evident at the periphery (b)

a

b

Fig. 5.16  Lupus miliaris disseminatus faciei in an Indian male (a). Dermoscopy reveals focal, yellowish-orange, structureless areas around follicles with diffuse erythema and vessels; keratotic plugs and scales are also seen (b). (Courtesy of Biswanath Behera, MD – Bhubaneswar, India)

References 1. Errichetti E, Lallas A.  Granulomatous non-infectious disorders. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 56–64. 2. Errichetti E, Sadek A, Ankad B, et  al. Non-infectious granulomatous disorders and connective tissue diseases. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 35–49. 3. Errichetti E, Stinco G. Dermatoscopy of granulomatous disorders. Dermatol Clin. 2018;36:369–75. 4. Errichetti E.  Dermoscopy of inflammatory dermatoses (inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80. 5. Errichetti E, Stinco G. Dermoscopy in general dermatology: a practical overview. Dermatol Ther (Heidelb). 2016;6:471–507.

6. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the international dermoscopy society. Eur J Dermatol. 2020;30:688–98. 7. Errichetti E, Ankad BS, Jha AK, et  al. International dermoscopy society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 8. Errichetti E, Lallas A, Apalla Z, Di Stefani A, Stinco G. Dermoscopy of granuloma annulare: a clinical and histological correlation study. Dermatology. 2017;233:74–9. 9. Errichetti E, Cataldi P, Stinco G. Dermoscopy in annular elastolytic giant cell granuloma. J Dermatol. 2019;46:e66–7. 10. Chauhan P, Adya KA. Dermatoscopy of cutaneous granulomatous disorders. Indian Dermatol Online J. 2021;12:34–44. 11. Conforti C, Dri A, Errichetti E, Zelin E, Zalaudek I, Di Meo N. Dermoscopic features of foreign body cutaneous granuloma: a case series. Dermatol Pract Concept. 2021;11:e2021025.

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Connective Tissue Diseases Enzo Errichetti, Balachandra S. Ankad, Biswanath Behera, and Aimilios Lallas

Contents 6.1 6.1.1  6.1.2  6.1.3 

Lupus Erythematosus  Introduction  Clinical Presentation  Dermoscopy 

 67  67  67  71

6.2 6.2.1  6.2.2  6.2.3 

Dermatomyositis  Introduction  Clinical Presentation  Dermoscopy 

 75  75  75  75

6.3 6.3.1  6.3.2  6.3.3 

 orphea and Systemic Sclerosis  M Introduction  Clinical Presentation  Dermoscopy 

 79  79  79  83

6.4 6.4.1  6.4.2  6.4.3 

Lichen Sclerosus  Introduction  Clinical Presentation  Dermoscopy 

 83  83  83  85

References 

6.1 Lupus Erythematosus 6.1.1 Introduction Lupus erythematosus (LE) is a chronic inflammatory autoimmune disease resulting from genetic, hormonal, and environmental factors [1–4]. It presents a wide spectrum of E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India B. Behera Department of Dermatology, and Venereology, AIIMS, Bhubaneswar, India A. Lallas First Department of Dermatology, Aristotle University of Thessaloniki, Thessaloniki, Thessaloniki, Greece

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manifestations, and several organs may be involved, with skin being one of the most commonly affected sites. Incidence in African Americans and Hispanics is usually higher than Caucasian, Asian, and Latin Americans [1–4]. Three main forms of cutaneous LE are typically recognized, including chronic cutaneous LE (CCLE), subacute cutaneous LE (SCLE), and acute cutaneous LE (ACLE), with the first one being the most frequent variant regardless the phototype and the second one being quite rare in skin of color [1–4].

6.1.2 Clinical Presentation Malar rash, also known as “butterfly” rash, is the main cutaneous manifestation of ACLE; it consists of sun-induced erythematous patches or plaques involving malar areas with sparing of nasolabial folds (Figs. 6.1a, 6.2, and 6.3a) [1–4]. Such lesions are typically more subtle and often leave

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_6

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Fig. 6.1  Malar rash in a Caucasian lady with acute lupus erythematosus (a). Dermoscopy reveals the so-called “inverse strawberry” pattern (red/ salmon-colored follicular dots surrounded by white halos) in lighter phototypes (b)

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Fig. 6.2  Malar rash in an Indian girl (a). Vessels (mainly linear/linear with short branches), scaling (sparse and perifollicular), and pigmented dots (magnification in the inset) are visible on dermoscopy (b)

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Fig. 6.3  Acute lupus erythematosus presenting as malar rash in a Caucasian girl (a). Dermoscopic examination shows dotted and linear vessels along with patchy white scales (b)

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p­ ost-­inflammatory hyperpigmentation in darker phototypes aspects of the upper extremities are the most commonly (Fig. 6.2a) [2]. Other possible ACLE-specific manifestations involved areas (Figs. 6.6a and 6.7a). In skin of color, lesions include broken and thinned hairs at the front hairline (“lupus often tend to show a brownish hue (Fig.  6.8a) or cause hair”), ungual changes (periungual erythema/pigmentation hypopigmentation (Fig. 6.9a) [1–4]. and red lunula), and multiple, erythematous, or brownish CCLE encompasses four main clinical variants, i.e., dis(dark phototypes) confluent macules and papules affecting coid LE (DLE), LE tumidus, lupus panniculitis, and chilsun-exposed areas (Figs. 6.4a and 6.5a) [1–4]. blain lupus, with the first form being by far the most common SCLE presents as erythematous scaly papules progress- form regardless the phototypes [1–4]. DLE manifests as erying to either annular or psoriasiform erythematous-­ thematous (especially in fair skin) or brownish (especially in desquamative patches/plaques; upper chest and extensor dark skin) papules progressing to roundish plaques with a

b

Fig. 6.4  Generalized acute lupus erythematosus in a Caucasian woman (a). Dermoscopy vessels (mainly sparse dotted) and patchy white/yellow scales/crusts over a hypopigmented background (b)

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Fig. 6.5  Generalized acute lupus erythematosus in an Indian man (a). Dermoscopic assessment displays patchy white scales, follicular plugs (arrowhead), and many brownish dots/globules (b)

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Fig. 6.6  Subacute cutaneous lupus erythematosus in a Caucasian man (a). Diffuse white scaling and mixed vascular morphology (linear and dotted) are visible on dermoscopy (b)

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Fig. 6.7  Subacute cutaneous lupus erythematosus in a Caucasian lady (a). Dermoscopic assessment displays peripheral white scales along with dotted (white arrowhead) and linear (black arrowhead) vessels (inset) (b)

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a

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Fig. 6.8  Subacute cutaneous lupus erythematosus in an Indian lady (a). Dermoscopy shows linear and linear-branching vessels as well as follicular plugs surrounded by brown halos (arrowhead) (b)

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Fig. 6.9  Subacute cutaneous lupus erythematosus in an Indian man (a). Dermoscopic examination displays bright white areas, mixed vascular findings (mainly linear and linear with branches vessels), and brown dots (b)

adherent scaling mainly involving the scalp, face, lips, and ears, with the last site being affected particularly in dark-­ skinned patients (Figs.  6.10a, 6.11, 6.12, 6.13, 6.14 and 6.15a) [1–4]. Lesions may heal leaving atrophy, hypo−/ hyperpigmentation and scarring, especially in darker phototypes in which a significant disfigurement may be seen (Figs. 6.16a, 6.17 and 6.18a) [1–4].

6.1.3 Dermoscopy Dermoscopic assessment of malar rash in ACLE mainly reveals an “inverse strawberry” pattern (red/salmon-colored

follicular dots surrounded by white halos) in lighter ­phototypes (Fig.  6.1b) and pinkish-white to reddish-white homogenous background with follicular plugs and brown dots/globules in dark-skinned patients (Fig. 6.2b) [1, 2, 5, 6]. Such differences are due to a higher tendency to follicular, sclerotic, or pigmentary reaction patterns typical of skin of color [2, 6]. Other common findings of malar rash reported in the literature regardless the phototype include white scaling and vessels (Figs. 6.2b and 6.3b) that usually present a dotted/linear morphology in fair skin and linear/linear with branches shape in dark skin [1, 2, 5–7]. When it comes to generalized ACLE, dotted and linear vessels along with patchy white scales are the most common findings in

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Fig. 6.10  Discoid lupus erythematosus (active lesions) in a Caucasian man (a). Dermoscopic assessment reveals follicular white plugs over a reddish background; linear-curved vessels are also seen (inset) (b)

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Fig. 6.11  Discoid lupus erythematosus (active lesions) in an Indian man (a). Dermoscopic examination shows follicular white and brown plugs over a reddish-brown background (b)

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Fig. 6.12  Discoid lupus erythematosus involving the ear in an Indian man (a). Dermoscopic assessment reveals follicular gray-brown plugs surrounded by brown pigmentation (b)

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Fig. 6.13  Discoid lupus erythematosus (early stages) in a Caucasian woman (a). Follicular dots and perifollicular white halos (“inverse strawberry” pattern) are event on dermoscopy (b)

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Fig. 6.14  Discoid lupus erythematosus involving the lip in a Caucasian man (a). Dermoscopy displays central crusting along with peripheral radially distributed white lines and linear vessels (b)

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Fig. 6.15  Discoid lupus erythematosus of the lip in an Indian woman (a). Peripheral radially distributed white lines and linear vessels along with some peripheral pigmented dots are visible on dermoscopic assessment; central erosion with orthogonal white lines is also evident (b)

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Fig. 6.16  Scarring stage of discoid lupus erythematosus in a Caucasian man (a). Bright white fibrotic structures (lines and structureless areas) as well as a polymorphous vascular pattern (including linear, linear-curved, and linear-branching vessels) are evident on dermoscopy (b)

a

Fig. 6.17  Scarring stage of discoid lupus erythematosus in an African American woman (a). Dermoscopy displays bright white structures, including white structureless areas and white dots; white and brown

a

b

follicular plugs and brown pigmentary structures are also seen (magnification in the inset) (b). (Courtesy of Richard P. Usatine, MD – San Antonio, USA)

b

Fig. 6.18  Scarring stage of discoid lupus erythematosus in an Indian man (a). Dermoscopic examination reveals diffuse bright white structureless areas, dots, and lines; some follicular plugs are also seen (b)

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Caucasians (Fig.  6.4b), while the same pattern as facial forms has been described in the literature for skin of color, though a higher prevalence of brown structureless areas is generally observed in extra-facial areas (Fig. 6.5b) [1, 2, 6, 7]. Ungual changes may also be seen on dermoscopy, with tortuous vessels of the proximal nail fold and periungual whitish or brownish areas/longitudinal melanonychia possibly visible in fair and dark skin, respectively [1, 2]. The main dermoscopic features of SCLE in lighter phototypes include diffuse or peripherally arranged whitish scales along with a mixed vascular pattern comprising linear, linear-­irregular, branching, and sparsely distributed dotted vessels over a pinkish-reddish background; focal orange areas may also be seen (Figs. 6.6b and 6.7b) [8]. In addition to such findings, white shiny structures, pigmentary structures, follicular plugging (sometimes surrounded by brown halos), and focal multicolored pattern (mix of white, pink, purple, and reddish-orange color thought to related to an increased vascularity) have been described in skin of color, with the first three findings possibly resulting from a higher tendency to fibrotic, pigmentary, and follicular reactions (Figs. 6.8b and 6.9b) [2, 9]. Moreover, in the authors’ experience, very dark phototypes vessels are difficult to see in SCLE lesions. Dermoscopic pattern of DLE typically changes based on the disease phase. In particular, in active inflammatory lesions, it consists of white (fair and dark skin) or brown (dark skin) follicular plugs, histologically related to follicular hyperkeratosis (along with melanin for brown plugs), on a reddish or brownish (dark skin) background and diffuse/central white scaling (Figs. 6.10b, 6.11 and 6.12b) [1, 2, 10–13]. Peripheral vessels (especially linear-curved but also dotted, linear, and linear with branches) may be seen, mainly in lighter phototypes (Fig.  6.10b) [1, 2, 10–13]. Of note, an “inverse strawberry” pattern typified by red follicular dots and perifollicular white halos may also be evident less commonly in inflammatory lesions affecting fair-skinned patients (Fig. 6.13b) [1, 2, 10–13]. Over the time, pigmentary structures are also often evident in skin of color, including brown perifollicular circles/semicircles and structureless areas, histologically related to basal layer hyperpigmentation, and/or brown/gray dots/globules corresponding to dermal pigment incontinence (Figs. 6.11b and 6.17b) [1, 2, 10–13]. In long-­ standing lesions, it is possible to appreciate a polymorphous vascular pattern (fair-skinned patients) as well as fibrotic white bright areas, including structureless, linear, or globular areas, with this last morphology being more frequent in darker phototypes due to the higher tendency to follicular fibrosis (Figs. 6.16b, 6.17 and 6.18b) [1, 2, 10–13]. Lips DLE usually features a central crust/erosion with peripheral radially distributed white lines and linear vessels (Figs. 6.14b and 6.15b); no follicular plugs is typically seen, while pigmented dots are often evident in skin of color (Fig. 6.15b) [1, 2, 14].

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6.2 Dermatomyositis 6.2.1 Introduction Dermatomyositis is an autoimmune inflammatory condition typically characterized by a myopathy of large proximal muscle groups (e.g., the upper arms and thighs) as well as cutaneous manifestations, with the latter occurring concomitantly, before or after muscular alterations or be the sole ­presentation of the disease (amyopathic dermatomyositis) [1, 2, 15, 16]. It may affect both children and adults, with possible involvement of several other organs, mainly including joints, lungs, heart, and esophagus [1, 2, 15, 16].

6.2.2 Clinical Presentation Several cutaneous manifestations may be observed in dermatomyositis, with “pathognomonic” and “characteristic” signs being the most relevant for the diagnosis [1, 2, 15, 16]. Gottron’s papules (Figs. 6.19a and 6.20a), heliotrope rash (Figs. 6.21a and 6.22a), and Gottron’s sign are included in the former group, while the second group encompasses shawl sign/V-sign (Figs. 6.23a and 6.24a), nail fold changes (Figs.  6.25, 6.26 and 6.27), photosensitive poikiloderma, and scalp scaly dermatosis [1, 2, 15, 16]. Further less specific/common cutaneous changes are periorbital edema/ facial swelling, panniculitis, calcinosis, erythroderma, vesicles/blisters, pruritus, cutaneous vasculitis, “mechanic’s hands,” “holster” sign, “callosity feet,” zebra-like erythema, and follicular hyperkeratosis [1, 2, 15, 16]. The main difference according to phototype on clinical ground concerns the hue of erythema as in Caucasians it is described as violaceous, while it tends to be subtle in skin of color, with hyperpigmentation being often the only visible finding (Figs.  6.19a, 6.19, 6.20, 6.21, 6.22, 6.23 and 6.24a) [1, 2, 15, 16]. Additionally, hypopigmented macules/papules may also be observed in darker phototypes (Fig. 6.28a).

6.2.3 Dermoscopy Dermoscopy may come in handy to facilitate the recognition of several skin changes typical of dermatomyositis, e.g., Gottron’s papules, heliotrope rash, Gottron’s sign, shawl sign/V-sign, scalp scaly dermatosis, nail fold changes, and cutaneous calcinosis [1, 2]. Gottron’s papules display findings that vary according to their phase, with active inflammatory lesions in lighter phototypes commonly featuring a pinkish background with or without dotted/linear-irregular vessels (dermal vasodilation) and central scaling/crusting (hyperkeratosis/necrosis) and

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Fig. 6.19  Gottron’s papules coalescing to form scaly plaques on the dorsal aspect of the hands in a Caucasian man (a). Dermoscopy displays dotted and linear vessels and white areas over a pinkish background (b)

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Fig. 6.20  Dermatomyositis in an Indian man (Gottron’s papules) of the dorsal aspect of the right hand (a). Dermoscopy shows multifocal white structureless areas along with brown hyperpigmentation (b).

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(From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

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Fig. 6.21  Heliotrope rash in a Caucasian woman (a). Dermoscopy reveals reticular vessels over a pinkish-purple background and white scaling (b)

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Fig. 6.22  Dermatomyositis involving the face in an Indian woman (a). Dermoscopy: diffuse brown background with white perifollicular areas; subtle linear vessels are also evident (b). (From “Dermoscopy in

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General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

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Fig. 6.23  Shawl sign in a Caucasian man (a). Dermoscopic examination shows include reticular vessels over a pinkish-purple background; perifollicular white areas are also evident (b)

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Fig. 6.24  Shawl sign in an Indian man (a). Dermoscopy displays brownish structureless areas and dots along with perifollicular white dots (arrowhead) and fibrotic white lines (b). (Courtesy of Payal Chauhan, MD – Dehradun, India)

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Fig. 6.25  Acral changes in a Caucasian woman suffering from dermatomyositis (a). Dermoscopic assessment of proximal nail fold shows dilated vessels surrounded by whitish areas (b)

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Fig. 6.26  Dermoscopy of proximal nail fold in dermatomyositis: hemorrhagic areas along with dilated vessels and hyperkeratotic cuticle (a); white areas, few vessels, and hyperkeratotic cuticle (b)

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Fig. 6.27  Hypertrophic proximal nail fold in an Indian patient suffering from dermatomyositis (a). Dermoscopy: hyperkeratotic cuticle along with focal white structureless areas and brown pigmentation (b).

b

(From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

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Fig. 6.28  Hypopigmented macules and papules in an Indian patient suffering from dermatomyositis (a). Dermoscopy shows white areas along with pigmentary star-like and polygonal brown areas (b)

advanced lesions mainly showing whitish areas (mucin depositions/fibrosis) in both fair and dark skin (Figs. 6.19b and 6.20b) [1, 2, 17]. Notably, vessels are difficult to see in skin of color and brown areas resulting from post-­ inflammatory basal cell layer hyperpigmentation are often evident (Figs.  6.20b), particularly in long-standing lesions [1, 2, 17]. The main dermoscopic features of erythematous patchy lesions (e.g., heliotrope rash, Gottron’s sign, and shawl sign/ V-sign) in fair-skinned patients include more or less focused reticular/linear-irregular vessels (corresponding to dilated subpapillary vascular plexus through the atrophic epidermis) over a pinkish-purple background and white scaling (related to hyperkeratosis) (Figs.  6.21b and 6.23b) [1, 2, 17]. However, vessels are typically less prevalent in skin of color, and a purplish background with perifollicular white areas (due to perifollicular mucin deposits) is sometimes the only visible finding (Figs. 6.22b and 6.24b) [1, 2]. Moreover, erythema may be replaced by a brown background (due to basal cell layer hyperpigmentation) with or without brown dots (related to dermal pigment incontinence) and white fibrotic areas in very dark phototypes (Fig. 6.24b) [1, 2]. Scalp scaly dermatosis in fair phototypes mainly shows enlarged tortuous capillaries, erythematous violaceous areas, and either perifollicular casts or interfollicular scaling; bushy capillaries, interfollicular/perifollicular pigmentation, and hair loss are other less common findings [1, 2]. On the other hand, white dots, brown honeycomb pigmentation, blue-gray speckled pigmentation, perifollicular scales, and interfollicular thin arborizing vessels are the main features in skin of color [1, 2]. Dermoscopic examination of proximal nail fold in fair-­ skinned patients may show significant features, including dilated vessels, hemorrhagic areas, thickened/hyperkeratotic cuticle over an erythematous background, and whitish areas

(possibly resulting from dermal edema/mucin deposits/fibrosis) (Figs. 6.25 and 6.26) [1, 2, 18]. In very dark phototypes, vascular structures and erythema may be difficult to appreciate and white areas, often coupled with brown hyperpigmentation, are the sole findings (Fig.  6.27b) [1, 2, 18]. Lastly, dermoscopy may also show white areas coupled with pigmentary findings in clinically hypopigmented lesions (Fig. 6.28b) and highlight cutaneous calcinosis by showing bright white areas [1, 2].

6.3 Morphea and Systemic Sclerosis 6.3.1 Introduction Morphea and systemic sclerosis (SSc) are two autoimmune connective tissue diseases whose main histological feature is an excessive collagen deposition that results into skin/subcutaneous tissues thickening and hardening [1, 2]. Whereas morphea is regarded as a condition limited to the skin, other organs may be affected in SSc [1, 2]. African Americans tends to display an earlier age of onset and a more severe course than Caucasians, while the incidence of morphea is higher in lighter phototypes [1, 2].

6.3.2 Clinical Presentation Morphea typically manifests as one or multiple inflammatory, edematous, reddish to grayish/brownish (especially in darker phototypes) patches that progress to hard, white sclerotic areas lacking of hair with a peripheral reddish/grayish-­ brownish border if margin is still active (Figs.  6.29a, 6.30 and 6.31a) [1, 2]. Long-standing sclerotic lesions may soften over the time and become atrophic with hypo- or hyperpig-

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Fig. 6.29  Morphea (inflammatory stage) in a Caucasian man (a). Dermoscopy reveals ill-defined dull white areas (arrowheads) along with subtle vessels (b)

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Fig. 6.30  Diffuse morphea of the abdomen in an Indian man (a). Dermoscopy displays ill-defined multifocal dull white areas along with bright white lines; brown structureless areas/lines are also evident (b).

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(From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

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Fig. 6.31  Morphea (sclerotic stage with peripheral activity) in a Caucasian woman (a). Dermoscopic examination shows ill-defined dull white areas along with unfocused linear and linear-branching vessels (b)

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mentation (Fig. 6.32a) [1, 2]. Several less common morphological forms of morphea do exist, i.e., guttate, keloidal/ nodular, bullous, linear, generalized, deep, and pansclerotic subtype [1, 2]. SSc initially manifests as symmetric swelling of the fingers progressing into sclerosis with ulcerations and decreased ability to move the skin [1, 2]. Skin lesions proximally a

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extend over the time, and nearly all the body surface area may be affected in most severe cases (Fig.  6.33a) [1, 2]. Hypopigmented areas with perifollicular sparing (“salt-and-­ pepper” appearance) is often seen in darker phototypes (Fig. 6.34a) [1, 2]. Raynaud phenomenon and proximal nail fold capillary changes typically precede or occur concomitantly to skin alterations (Figs. 6.35 and 6.36) [1, 2]. b

Fig. 6.32  Morphea (long-standing lesions with central hyperpigmentation and peripheral activity) in a Caucasian woman (a). Dermoscopy displays ill-defined dull white areas as well as unfocused linear/linear-branching purple vessels (b)

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Fig. 6.33  Extensive systemic sclerosis in a Caucasian man (a). Dermoscopic assessment shows bright white sclerotic areas with a variable shade in the context of the same lesion and a few fine linear-branching vessels (b)

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Fig. 6.34  Systemic sclerosis in an Indian woman with skin sclerosis and depigmented areas (a). Dermoscopy reveals bright white sclerotic areas with perifollicular pigmentation due to sparing of perifollicular areas (b)

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Fig. 6.35  Dermoscopy of proximal nail fold in systemic sclerosis in Caucasians: dilated vessels and hyperkeratotic cuticle (a); hemorrhagic areas, avascular areas, and hyperkeratotic cuticle (b)

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Fig. 6.36  Systemic sclerosis in an Indian woman with acral depigmentation (a). Dermoscopy displays a thickened/hyperkeratotic cuticle, hemorrhagic spots, and few distorted capillaries in the context of avascular areas (b)

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6.3.3 Dermoscopy The main dermoscopic clue of morphea in both fair and dark skin consists in the presence of focal (more common) or diffuse dull white areas with ill-defined margins (also referred to as “white clouds” and “white fibrotic beams”) histologically resulting from fibrosis in the deep dermis (Figs. 6.29b, 6.30, 6.31 and 6.32b) [1, 2, 12, 19]. Although these structures are more prevalent in clinically sclerotic lesions, they may also be seen even when sclerosis is not clearly evident on clinical ground (Fig. 6.29b) [1, 2, 12, 19]. Additionally, vessels (especially linear-irregular, but also dotted and linear-­ branching) may be frequently seen in light phototypes (Figs.  6.29b, 6.31b,6.32b), while they are less common in skin of color, in which it is often possible to appreciate pigmentary structures, such as brown dots (related to dermal pigment incontinence) and brown structureless areas/lines (corresponding to basal layer pigmentation) (Fig. 6.30b) [1, 2, 12, 19]. Other dermoscopic features mainly related to darker skin types include patchy brown scales (due to hyperkeratosis along with melanin exfoliation), perifollicular white areas (related to selective perifollicular fibrosis), and white lines (localized dermal fibrosis) (Fig. 6.30b) [1, 2, 12]. SSc shares the same dermoscopic features as morphea, yet two peculiarities are reported in the former, i.e., a more variable shade of white in the context of the same lesion (likely resulting from a different deepness of fibrosis) (Fig.  6.33b) and the presence of intermingled brownish structureless areas, particularly perifollicular pigmentation (due to perifollicular sparing), especially in skin of color (Fig. 6.34b) [1, 2]. Dermoscopic examination may also show changes of proximal nail fold, including a disrupted vascular configuration, with either capillary dilatation and giant capillaries (early cases) or avascular areas (advanced cases), hem-

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orrhagic spots, and a thickened/hyperkeratotic cuticle (Figs. 6.35 and 6.36b) [1, 2]. Of note, the vascular findings are difficult to see in darker phototypes, except if areas of depigmentation (Fig. 6.36b) [2, 12].

6.4 Lichen Sclerosus 6.4.1 Introduction Lichen sclerosus (LS) is a chronic, scleroatrophic, inflammatory, and autoimmune dermatosis that mainly involves anogenital area, yet extragenital (cutaneous) lesions may occur in a subset of patients, with or without anogenital lesions [1, 2].

6.4.2 Clinical Presentation LS in Caucasians manifests as white, polygonal papules often coalescing into plaques with variable size and shape, whose surface may be smooth or show telangiectasias, ­purpura, fissures, or erosions (Figs. 6.37a and 6.38a) [1, 2]. Moreover, active extragenital lesions may also feature follicular plugs as well as scaling or hyperkeratosis [1, 2]. With disease progression, lesions tend to become more atrophic and scarring, with possible functional sequelae on anogenital areas (Fig.  6.39a) [1, 2]. In very dark skin, lesions may sometimes appear as hyperpigmented patches (especially in long-­ standing ones) (Fig.  6.40a) [1, 2]. Extragenital involvement is typically asymptomatic, whereas anogenital lesions often cause itching, soreness, dyspareunia, dysuria, discomfort with defecation, and/or bleeding [1, 2].

b

Fig. 6.37  Lichen sclerosus (inflammatory lesions) in a Caucasian girl (a). Dermoscopic examination reveals multiple follicular plugs over a white background and a purple rim (b)

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Fig. 6.38  Lichen sclerosus (atrophic lesions) in a Caucasian woman (a). Dermoscopy shows multiple bright white areas as well as hemorrhagic spots (b)

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Fig. 6.39  Lichen sclerosus (hypopigmented lesions) in an Indian man (a). Dermoscopic assessment displays gray and brown follicular plugs over a bright white background (b)

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Fig. 6.40  Lichen sclerosus (hyperpigmented lesions) in a Caribbean woman (a). Dermoscopy reveals perifollicular white areas along with brown follicular plugs (b)

6  Connective Tissue Diseases

6.4.3 Dermoscopy The main dermoscopic clues of cutaneous lesions of LS include bright white areas (focal or diffuse) along with white, yellow, or brownish (dark skin) follicular plugs histologically related to homogenous fibrosis/hyalinization of the superficial dermis and follicular hyperkeratosis, respectively (Figs. 6.37b, 6.39b and 6.40b) [1, 2, 12, 19]. Furthermore, additional findings seen in both light and dark phototypes include white scales (resulting from hyperkeratosis), white perpendicular lines (resulting from dermal fibrosis), perifollicular white color (more common in dark skin for a higher tendency to perifollicular fibrosis), purpuric dots/areas (dermal hemorrhages), and linear vessels with branches (especially in fair skin) (Figs. 6.37b, 6.39b, 6.40b) [1, 2, 12, 19]. Of note, pigmentary features, such as brown structureless areas (due to basal cell layer hyperpigmentation) and dots (due to dermal pigment incontinence), may also be observed in skin of color, particularly in long-standing lesions [1, 2, 12, 19]. Dermoscopic pattern of anogenital lesions is the same as skin lesions, except for the absence of follicular plugs because of the lack of follicles on mucosae (apart from skin areas of anogenital areas) [1, 2].

References 1. Errichetti E, Lallas A.  Connective tissue diseases. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 65–85. 2. Errichetti E, Sadek A, Ankad B, et  al. Non-infectious granulomatous disorders and connective tissue diseases. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 35–49. 3. Grönhagen CM, Nyberg F.  Cutaneous lupus erythematosus: an update. Indian Dermatol Online J. 2014;5:7–13. 4. Uva L, Miguel D, Pinheiro C, Freitas JP, Marques Gomes M, Filipe P.  Cutaneous manifestations of systemic lupus erythematosus. Autoimmune Dis. 2012;2012:834291. 5. Errichetti E, Lallas A, De Marchi G, Apalla Z, Zabotti A, De Vita S, Stinco G. Dermoscopy in the differential diagnosis between malar rash of systemic lupus erythematosus and erythematotelangiectatic rosacea: an observational study. Lupus. 2019;28:1583–8.

85 6. Behera B, Palit A, Sethy M, Nayak AK, Dash S, Ayyanar P. Dermoscopic features of acute cutaneous lupus erythematosus: a retrospective analysis from a tertiary care Centre of East India. Australas J Dermatol. 2021;62:364–9. 7. Apalla Z, Papadimitriou I, Iordanidis D, et al. The dermatoscopic spectrum of cutaneous lupus erythematosus: a retrospective analysis by clinical subtype with clinicopathological correlation. Dermatol Ther. 2020;33:e14514. 8. Errichetti E, Piccirillo A, Viola L, Stinco G. Dermoscopy of subacute cutaneous lupus erythematosus. Int J Dermatol. 2016;55:e605–7. 9. Behera B, Nayak AK, Dash S, Sethy M. Subacute cutaneous lupus erythematosus: diagnosis and follow up by dermoscopy. Indian Dermatol Online J. 2021;12:755–7. 10. Errichetti E.  Dermoscopy of inflammatory dermatoses (Inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80. 11. Errichetti E, Zalaudek I, Kittler H, et  al. Standardization of dermoscopic terminology and basic dermoscopic parameters to evaluate in general dermatology (non-neoplastic dermatoses): an expert consensus on behalf of the international dermoscopy society. Br J Dermatol. 2020;182:454–67. 12. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the international dermoscopy society. Eur J Dermatol. 2020;30:688–98. 13. Errichetti E, Ankad BS, Jha AK, et  al. International dermoscopy society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 14. Jha AK, Sławińska M, Vinay K, et  al. Dermoscopic features of actinic cheilitis and other common inflammatory cheilitis: a multicentric retrospective observational study by the international dermoscopy society. Dermatology. 2022;7:1–6. 15. Dourmishev LA, Dourmishev AL.  Cutaneous manifestations of dermatomyositis. In: Dourmishev LA, Dourmishev AL, editors. Dermatomyositis: advances in recognition, understanding and management. 1st ed. Sofia: Springer; 2009. p. 43–53. 16. Mendese G, Mahalingam M.  Histopathology of Gottron's papules—utility in diagnosing dermatomyositis. J Cutan Pathol. 2007;34:793–6. 17. Errichetti E, Stinco G. The practical usefulness of dermoscopy in general dermatology. G Ital Dermatol Venereol. 2015;150:533–46. 18. Hasegawa M. Dermoscopy findings of nail fold capillaries in connective tissue diseases. J Dermatol. 2011;38:66–70. 19. Errichetti E, Lallas A, Apalla Z, Di Stefani A, Stinco G. Dermoscopy of morphea and cutaneous lichen sclerosus: clinicopathological correlation study and comparative analysis. Dermatology. 2017;233:462–70.

7

Facial Inflammatory Dermatoses Balachandra S. Ankad, Shishira Jartarkar, Ibrahima Traoré, Biswanath Behera, and Enzo Errichetti

Contents 7.1 7.1.1  7.1.2  7.1.3 

Acne Vulgaris  Introduction  Clinical Presentation  Dermoscopy 

 87  87  88  88

7.2 7.2.1  7.2.2  7.2.3 

Rosacea  Introduction  Clinical Features  Dermoscopy 

 90  90  90  90

7.3 7.3.1  7.3.2  7.3.3 

Seborrheic Dermatitis  Introduction  Clinical Presentation  Dermoscopy 

 92  92  92  92

7.4 7.4.1  7.4.2  7.4.3 

Pseudofolliculitis  Introduction  Clinical Presentation  Dermoscopy 

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7.5 7.5.1  7.5.2  7.5.3 

Granuloma Faciale  Introduction  Clinical Features  Dermoscopy 

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References 

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7.1 Acne Vulgaris B. S. Ankad (*) Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India S. Jartarkar Vydehi Institute of Medical Sciences and Research Centre, Bengaluru, India I. Traoré Dermatological Clinic, Conakry, Guinea B. Behera Department of Dermatology, and Venereology, AIIMS, Bhubaneswar, India

7.1.1 Introduction Acne vulgaris (AV) is an inflammatory disease of the pilosebaceous unit, mainly affecting adolescents and occasionally adults of every phototype [1]. The pathogenesis is multifactorial, and it occurs due to a complex interplay between follicular hyperkeratinization, seborrhea, and altered bacterial colonization (primarily by Cutibacterium acnes), with consequent release of various inflammatory mediators like IL-1, TNF alpha [2].

E. Errichetti Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_7

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7.1.2 Clinical Presentation AV has a variable clinical presentation, and its spectrum includes comedones (open and closed) and inflammatory lesions, such as papules, pustules, and nodules (Figs. 7.1a, 7.2, 7.3, 7.4 and 7.5a) [3–5]. The face is the most frequently involved area, followed by the upper chest and upper back [3–5]. Open comedones (blackheads) appear as blackish spots as a result of accumulation of sebum, keratin, and skin debris in the pilosebaceous orifice, whereas closed comedones (whiteheads) present as small whitish- or skin-colored papules (Figs. 7.1a, 7.2, 7.3 and 7.4a) [3–5]. Redness of inflammatory lesions is more difficult to see in very dark phototypes,

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yet they often tend to leave post-inflammatory hyperpigmented macules in such patients (Figs. 7.3a and 7.5a) [3–5]. Additionally, nodulocystic lesions are less frequent in skin of color but often cause hypertrophic scarring and keloids when they occur [3–5].

7.1.3 Dermoscopy Dermoscopic findings of AV vary depending on the type of lesion present [4, 5]. In both light and dark phototypes, open comedones are seen as dilated pores filled with brownish/grayish keratin plugs (Figs. 7.1b, 7.2 and 7.3b), while closed comedones appear as round skin-colored or white

b

Fig. 7.1  Acne vulgaris in a Caucasian boy with papules, pustules, and comedones (a). Dermoscopy reveals closed (white arrowhead) and open (black arrowhead) comedones surrounded by an erythematous halo (b)

a

Fig. 7.2  Acne vulgaris with comedones and papulopustular lesions in a lighter-skinned (phototype III) Indian girl (a). Dermoscopic examination shows an erythematous globule (papule) and an open comedone

b

(dilated pore filled with grayish keratotic plug and surrounded by an erythematous halo) (b)

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Fig. 7.3  Acne vulgaris in an African woman with papules and comedones (a). Dermoscopy displays an open comedone (dilated pore filled with a gray keratotic plug with a brown halo) (b)

a

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Fig. 7.4  Comedonal acne in an African girl (a). A closed comedone appearing as a white round structure with a brown halo is seen on dermoscopy (b)

areas (Fig. 7.4b) [4, 5]. Of note, both types of comedones are commonly surrounded by a brown halo in dark phototypes (Figs. 7.3b and 7.4b) [4, 5]. On the other hand, papules manifest as more or less evident (based on the skin type) reddish round areas, sometimes associated with dot-

ted vessels (especially in fair-skinned patients), whereas pustular acne shows dull white to yellow globules with erythematous periphery (Figs.  7.2b and 7.5b) [4, 5]. Nodulocystic acne reveals red areas, white globules (pustules), and scales [4, 5].

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a

b

Fig. 7.5  Papulopustular acne in an African boy (a). Dermoscopic examination reveals reddish round areas with a subtle brown halo (b)

7.2 Rosacea 7.2.1 Introduction Rosacea is a common, chronic inflammatory multifactorial disorder primarily affecting the face typified by an abnormal vasomotor response resulting in persistent vasodilatation and increased vascular permeability [4, 5]. A Gram-negative Demodex folliculorum-associated bacteria, called Bacillus oleronius, is supposed to play a role in triggering innate immune system response [4, 5]. Rosacea is much more common in lighter phototypes, yet it may also occur in skin of color [4, 5].

7.2.2 Clinical Features The most commonly involved areas in rosacea include forehead, cheeks, nose, and chin; from a morphological point of view, manifestations vary based on the clinical subtype [4, 5]. Three main forms are recognized, including erythematotelangiectatic, papulopustular, and glandular variants [4, 5]. The first subtype is mainly seen in lighter phototypes and manifests as flushing, persistent erythema, and telangiectasias (Fig. 7.6a), with findings being less evident in skin of color (Fig. 7.7a). On the other hand, papulopustular and glandular variants present as papules/pustules on an erythematous background and disfiguring skin enlargements (e.g., rhinophyma),

respectively [4, 5]. Other less frequent variants include granulomatous (Figs. 7.8a and 7.9a) and ocular rosacea [4, 5].

7.2.3 Dermoscopy The most characteristic diagnostic criterion for rosacea is the presence of linear vessels arranged in a reticular pattern to form the so-called vascular polygons histologically related to dilated vessels in the subpapillary plexus [4–9]. Such a finding is seen in both light and dark skin and in every clinical type of rosacea (Figs. 7.6b and 7.7b) yet is more evident in fair-skinned patients with erythematotelangiectatic presentation [4–12]. On the other hand, unlike lighter phototypes, several pigmentary structures may be observed in skin of color, such as periosteal brown globules and circles (Fig. 7.7b) [4–12]. Further findings include round reddish and yellow areas (papulopustular rosacea), yellow dilated follicular openings (filled with sebum – typical of glandular rosacea), follicular plugging, and superficial white/yellow scales [4–11]. Occasionally, protruding follicular plugs (related to the presence of a mixture of keratin and Demodex mites in the follicles) may be seen [4–9]. Finally, besides vascular polygons, granulomatous rosacea shows orange-colored areas related to the presence of dermal granulomas on histology (Fig.  7.8b); they are usually less evident in dark skin (Fig. 7.9b) [4–9].

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Fig. 7.6  Erythematotelangiectatic rosacea in a Caucasian woman (a). Linear blurred vessels arranged in a reticular pattern (vascular polygons) are evident on dermoscopy (b)

a

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Fig. 7.7  Erythematotelangiectatic rosacea in a Caribbean woman (a). Dermoscopy shows linear blurred vessels arranged in a reticular pattern (vascular polygons) along with periosteal brown pigmentation (brown circles—arrowhead) (b)

a

b

Fig. 7.8  Granulomatous rosacea in a Caucasian man (a). Dermoscopic assessment displays vascular polygons along with multiple orange structureless areas (b)

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b

Fig. 7.9  Granulomatous rosacea in an Indian woman (a). Many vascular polygons are visible on dermoscopy along with subtle orangish structureless areas (arrowhead) (b)

7.3 Seborrheic Dermatitis 7.3.1 Introduction Seborrheic dermatitis (SD) is a common inflammatory dermatosis typically involving areas rich in sebaceous glands whose pathogenesis is linked to individual’s sebum composition and immune response to Malassezia [4, 5]. It is commonly observed in both fair- and dark-skinned patients, with two main forms being reported, i.e., a self-limiting infantile variant (from birth to 3 months of age) and a chronic/relapsing adult variant (peaking at ages 30–60) [4, 5].

7.3.2 Clinical Presentation Infantile SD manifests as yellowish, greasy scale on the scalp (“cradle cap”) or erythematous patches, with or without yellowish/grayish scaling involving face and folds (retroauricular areas, axillae, and groins) (Figs. 7.10a and 7.11a) [4, 5]. Adult type presents as erythema and yellowish/grayish greasy scaling affecting sebaceous areas, such as nasolabial folds, beard area, eyebrows, retroauricular area, and mid chest [4, 5]. Erythema in very dark-skinned patients is more faint, while post-inflammatory hypopig-

mented patches are quite common in skin of color (Fig. 7.11a) [4, 5].

7.3.3 Dermoscopy Dermoscopy of SD reveals clustered vessels (mainly dotted but also linear), corresponding to dilated dermal vessels, and patchy scales (due to hyperkeratosis and spongiosis) that may be white, yellow, or brown, with the latter color being seen only in darker phototypes as they are more prone to melanin exfoliation (Figs. 7.10b and 7.11b) [4, 5, 10–12]. Of note, vessels may be not easy to be appreciated in skin of color, unless there are white structureless areas that are often seen in dark-skinned patients due to post-inflammatory hypopigmentation (Fig. 7.11b) [4, 5, 10–12]. Follicular findings are also commonly found in dark phototypes due to the higher tendency toward follicular reaction patterns, including “sebum excrescences” (white/yellow, protruding/non-­ protruding, broad greasy follicular plugs due to sebum and keratin accumulation in the follicles), perifollicular scaling, and perifollicular hypopigmentation (Fig.  7.11b) [5]. Of note, “sebum excrescences” differ from protruding follicular plugs seen in demodicosis (“Demodex tails”) as the former are broader and less protruding [5].

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Fig. 7.10  Seborrheic dermatitis in a Caucasian man (a). Clustered dotted vessels as well as patchy white-gray scales are evident on dermoscopy (b)

a

b

Fig. 7.11  Seborrheic dermatitis in an African woman (a). Dermoscopy shows greasy white-gray scales along with ill-defined hypopigmented areas that are prominent around follicular ostia (black arrowhead);

“sebum excrescences” (arrow), perifollicular scaling (white arrowhead), and sparse dotted vessels are also seen (b)

7.4 Pseudofolliculitis

may sometimes be observed, with a higher prevalence in skin of color due to a higher tendency to fibrotic reactions [4, 5, 13]. Beard area is the most commonly involved site, but it can occur in any other areas with terminal hair that undergo shaving; the most frequent area in men is anterior neck followed by cheeks and chin (Figs. 7.12a and 7.13a) [4, 5, 13].

7.4.1 Introduction Pseudofolliculitis is a chronic inflammation of follicular and perifollicular skin occurring as a result of ingrown hair secondary to hair removal/shaving [4, 5, 13]. It is more common in people with curly hair due to increased chances of aberrant hair entry, so it is often seen in African patients [4, 5, 13].

7.4.2 Clinical Presentation It is clinically characterized by itchy erythematous papules and pustules that often heal leaving post-inflammatory hyperpigmentation in darker phototypes [4, 5, 13]. Scarring

7.4.3 Dermoscopy Dermoscopy typically shows ingrown hair that is apparently attached at both the ends; such a finding is often referred to as “handlebar” sign (Figs. 7.12b and 7.13b) [4, 5, 14]. The ingrown end of the hair, sometimes, shows signs of inflammation like scaling, erythema, or yellow areas (representing pustules) [4, 5, 14]. White areas indicating fibrosis and dot-

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a

b

Fig. 7.12  Pseudofolliculitis in a phototype IV Indian man (a). Dermoscopic examination shows reveals the so-called “handlebar” sign (ingrown hair that is apparently attached at both the ends); bluish discoloration of hair that is buried under skin is also seen (arrowhead) (b)

a

b

Fig. 7.13  Pseudofolliculitis in a phototype VI African man with curly hair (a). Dermoscopy displays the “handlebar” sign (ingrown hair that is apparently attached at both the ends) along with perifollicular white

scaling and fibrotic bright white areas (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

ted/linear irregularly arranged vessels may also be observed, yet the former finding is seen especially in skin of color (as it is more prone to fibrotic reaction), while the latter is mainly found in lighter phototypes (Figs.  7.12b and 7.13b) [4, 5, 14]. Another dermoscopic clue to the diagnosis visible regardless skin type is the presence of buried hair shafts, seen as bluish lines [4, 5, 14].

chronic leukocytoclastic vasculitis with fibrosing evolution [4, 5]. It is commonly seen in middle-aged males with light phototypes, but it may also affect patients with skin of color [4, 5].

7.5 Granuloma Faciale 7.5.1 Introduction Granuloma faciale (GF) is an uncommon chronic benign dermatosis of unknown etiology histologically characterized by a

7.5.2 Clinical Features It clinically presents as solitary/multiple, well-defined, asymptomatic papules, plaques, or nodules whose shade range from reddish or violaceous/brown in fair-skinned patients (Fig. 7.14a) to purple-brown or brown in dark skin (Fig.  7.15a) [4, 5]. Lesions mainly involve face, yet extra-­ facial manifestations may be observed [4, 5]. Of note, follicular ostia accentuation (peau d’orange) may be seen in case of lesions located on the face (Fig. 7.14a) [4, 5].

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Fig. 7.14  Granuloma faciale of the nose in a Caucasian man (a). Dermoscopic assessment shows orange background, dilated follicular ostia, and blurred vessels (arrowhead) (b)

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Fig. 7.15  Granuloma faciale of the nose in an Indian woman (a). A brown background along with dilated follicular openings is evident on dermoscopy (b)

7.5.3 Dermoscopy The main dermoscopic findings of GF include prominent follicular orifices, thought to be the result of the lack of inflammation of the superficial dermis (“narrow grenz zone”) with consequent laxity of the follicular ostia, and orange areas (focal or diffuse), due to the presence of hemosiderin in the dermis (Figs. 7.14b and 7.15b) [4–6, 15]. Of note, these areas may show a brownish hue in skin of color (Fig. 7.15b) [5]. Several additional features have been reports, i.e., linear branching vessels (difficult to see in darker phototypes), whitish perifollicular halo, pigmentation structures (especially in skin of color), follicular plugs, and yellowish scales (Fig.  7.14b) [4–6, 15]. Furthermore, whitish streaks and whitish-grayish structureless areas related to dermal fibrosis

may also be seen in long-standing lesions, whereas purpuric spots resulting from erythrocytes extravasation may be observed in early phases [4–6, 15].

References 1. Kurokawa I, Danby FW, Ju Q, et  al. New developments in our understanding of acne pathogenesis and treatment. Exp Dermatol. 2009;18:821–32. 2. Alfaro-Castellon P, Mejia-Rodriguez SA, Valencia-Herrera A, Ramirez S, Mena-Cedillos C. Dermoscopy distinction of eruptive vellus hair cysts with molluscum contagiosum and acne lesions. Pediatr Dermatol. 2012;29:772–3. 3. Rather S, Kansal M.  Facial dermatoses. In: Ankad BS, Bhat YJ, Rambhia KD, editors. IADVL atlas of dermoscopy. New Delhi: Jaypee Brothers Medical Publishers; 2022. p. 145–83.

96 4. Errichetti E, Kaliyadan F, Lacarrubba F, Verzì AE, Micali G, Lallas A. Facial dermatoses. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 86–96. 5. Errichetti E, Kaliyadan F, Puravoor J, Ankad B, Akay BN, Lallas A. Facial inflammatory dermatoses. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 51–6. 6. Lallas A, Argenziano G, Apalla Z, et al. Dermoscopic patterns of common facial inflammatory skin diseases. J Eur Acad Dermatol Venereol. 2014;28:609–14. 7. Nayak SS, Mehta HH, Gajjar PC, Nimbark VN.  Dermoscopy of general dermatological conditions in Indian population: a descriptive study. Clin Dermatol Rev. 2017;1:41–51. 8. Ankad BS, Mukherjee SS, Jaju PS.  Vascular diseases. In: Ankad BS, Mukherjee SS, Nikam BP, editors. Dermoscopy histopathology correlation. Singapore: Springer; 2021. p. 185–213. 9. Kara YA, Ozden HK. Dermoscopic findings of rosacea and demodicidosis. Indian J Dermatol. 2021;66:165–8. 10. Errichetti E, Zalaudek I, Kittler H, et  al. Standardization of dermoscopic terminology and basic dermoscopic parameters to evalu-

B. S. Ankad et al. ate in general dermatology (non-neoplastic dermatoses): an expert consensus on behalf of the international dermoscopy society. Br J Dermatol. 2020;182:454–67. 11. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the international dermoscopy society. Eur J Dermatol. 2020;30:688–98. 12. Errichetti E, Ankad BS, Jha AK, et al. International Dermoscopy society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 13. Ogunbiyi A.  Pseudofolliculitis barbae; current treatment options. Clin Cosmet Investig Dermatol. 2019;12:241–7. 14. Kaliyadan K, Kuruvilla J, Al Ojail HY, Quadri SA.  Clinical and dermoscopic study of pseudofolliculitis of the beard area. Int J Trichol. 2016;8:40–2. 15. Errichetti E.  Dermoscopy of inflammatory dermatoses (Inflammoscopy): an up-to-date overview. Dermatol Pract Concept. 2019;9:169–80.

8

Common Hyperpigmented Dermatoses Shekhar Neema, Balachandra S. Ankad, and Enzo Errichetti

Contents 8.1 8.1.1  8.1.2  8.1.3 

Lichen Pigmentosus  Introduction  Clinical Presentation  Dermoscopy 

 98  98  98  98

8.2 8.2.1  8.2.2  8.2.3 

Ashy Dermatosis  Introduction  Clinical Presentation  Dermoscopy 

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8.3 8.3.1  8.3.2  8.3.3 

Melasma  Introduction  Clinical Presentation  Dermoscopy 

 101  101  101  101

8.4 8.4.1  8.4.2  8.4.3 

Friction Melanosis  Introduction  Clinical Presentation  Dermoscopy 

 103  103  103  103

8.5 8.5.1  8.5.2  8.5.3 

Acanthosis Nigricans  Introduction  Clinical Presentation  Dermoscopy 

 104  104  104  105

8.6 8.6.1  8.6.2  8.6.3 

Post-inflammatory Hyperpigmentation  Introduction  Clinical Presentation  Dermoscopy 

 105  105  105  105

8.7 8.7.1  8.7.2  8.7.3 

 evus of Ota and Becker Nevus  N Introduction  Clinical Presentation  Dermoscopy 

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References 

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S. Neema Department of Dermatology, Armed Forces Medical College, Pune, India B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_8

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8.1 Lichen Pigmentosus 8.1.1 Introduction Lichen pigmentosus (LP) is a variant of lichen planus most commonly occurring in females during the III–V decades of life [1, 2]. It is mainly seen in individuals with darker skin phototype, especially Indian, Latin American, Asian, and African people, though it may also affect fair-skinned patients [1, 2]. The exact cause of LP is not known, yet many factors have been implicated in causation, e.g., hormonal factors (onset in perimenopausal age group), hepatitis C virus infection, topical use and consumption of mustard oil, hair dye, henna, nickel allergy, and environmental pollution [3].

8.1.2 Clinical Presentation It presents as slowly progressive discrete brown macules usually with sharp margins and mainly involving face (especially in dark skin), neck, and flexures, yet arms and legs may also be involved (Figs. 8.1a, 8.2 and 8.3a); lesions are mostly asymptomatic, but itching may be present in active phases [4–7]. Compared to lighter phototypes (Fig.  8.1a), lesions are darker or brown-gray and more persistent in skin of color (Figs. 8.2a and 8.3a), with pigmentation distribution pattern being more variable as it may be diffuse (the most

a

common presentation in both fair and dark skin) but also reticular, perifollicular, or annular [5–7]. Additionally, LP in dark-skinned patients is not uncommonly associated with lichen planopilaris, and often lesions are larger (i.e., patches) due to the confluence of macules (Fig. 8.2a) [6].

8.1.3 Dermoscopy From a dermoscopic point of view, LP is typified by the presence of pigmented dots/globules histologically corresponding to pigment incontinence (free melanin or melanophages) in the papillary dermis resulting from dermo-epidermal junction damage due to band-like inflammatory infiltrate [5–8]. Color of the dots/globules is either brown or gray, depending on the deepness of pigment deposition in the dermis (papillary and superficial reticular dermis, respectively); a combination of brown and gray dots/globules is often seen (Figs.  8.1b, 8.2 and 8.3b) [5–8]. Of note, in very dark phototypes (V/VI), pigmentation is so intense that dots/globules may appear black (Fig.  8.2b) or coalesce into a diffuse pigmentation (though some dots are usually still visible) (Fig. 8.3b) [5–8]. Arrangement of the dots/globules may be periosteal (around eccrine and follicular ostia) on the face (Fig. 8.3b) and displays a typical sparing of the skin furrows, especially in skin of color [5–8]. Additionally, hem-like (intermittent linear) or arcuate (arciform) distribution patterns have also been reported in dark phototypes (mainly on the extremities) [5–8].

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Fig. 8.1  Lichen pigmentosus in a Caucasian man (a). Dermoscopy reveals brown and gray dots and globules (b)

8  Common Hyperpigmented Dermatoses

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Fig. 8.2  Diffuse lichen pigmentosus with sharp-demarcated lesions in cubital flexures in an African boy (a). Brown dots are seen on dermoscopic examination; some dots are so pigmented that feature a black hue (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

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Fig. 8.3  Lichen pigmentosus of the face in an Indian man (a). Dermoscopic assessment reveals brown dots, with some of them coalescing into larger pigmented areas; follicular/sweat glands ostia are typically spared (b)

8.2 Ashy Dermatosis

8.2.2 Clinical Presentation

8.2.1 Introduction

AD is usually typified by an insidious onset, with gradually progressive asymptomatic hyperpigmentation, albeit a minority of patients may complain about pruritus [4, 5, 9]. The lesions present a gray-bluish shade (darker in skin of color) and ill-defined margins; are symmetrically distributed over body; and start as small size macule slowly enlarging to form larger patches (especially in darker phototypes) over weeks (Figs. 8.4a, 8.5 and 8.6a); a slightly raised erythematous border may be seen in active phases, yet it may not be appreciable in individuals with darker skin [4, 5, 9]. Trunk is the most involved site in both fair and dark skin, though face

Ashy dermatoses (AD), also known as erythema dyschromicum perstans, are a gradually progressive pigmentary dermatosis mainly occurring in young adults [9, 10]. Although its etiopathogenesis is yet to be understood, a response to antigenic stimulation, including infections (e.g., hepatitis C virus and intestinal parasitoses) or drugs (e.g., radiocontrast media, ammonium nitrate, ethambutol, omeprazole, and fluoxetine), may play a role in disease onset. It is more common in Latin America and in darker skin (Fitzpatrick IV-V phototypes) [9, 10].

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Fig. 8.4  Ashy dermatosis in a Caucasian girl (a). Small bluish dots are evident on dermoscopy (b)

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Fig. 8.5  Ashy dermatosis in an Indian boy (a). Dermoscopic examination shows bluish dots that coalesce into larger pigmented areas (b)

(especially in skin of color) (Fig. 8.6a), neck, and upper and lower limbs may also be involved [4, 5, 9]. Hypopigmented macules/areas may also be found in dark phototypes [4, 5, 9].

8.2.3 Dermoscopy Dermoscopy of AD overlaps with LP as histopathology of these two conditions is similar, yet the deeper location of pigment incontinence gives rise to some differences [4–8, 11]. In detail, the main dermoscopic feature of AD in both light and dark phototypes consists in the presence of gray and blue dots (with the latter being more specific) ­histologically corresponding to melanophages/melanin deposits in superficial and deep reticular dermis, respectively (Figs.  8.4b, 8.5 and

8.6b) [4–8, 11]. Notably, differently from LP, globules are usually less common in AD as pigment incontinence is located more deeply, thus being further from skin surface, yet more diffuse pigmented areas may be noticed in very dark phototypes (V and VI) (Fig. 8.5b) [4–8, 11]. The abovementioned dermoscopic structures are seen either in pigmented lesions but also in hypopigmented ones. As described for LP, dots are distributed in a periosteal pattern on the face (Fig. 8.6b) [4–8, 11]. A bluish background (with ostial sparing on the face) is often seen and may be marked in skin of color, making dots more difficult to be seen (Fig.  8.5b) [4–8, 11]. Other less common findings described in fair-skinned patients include pink background (early stages) and irregular-linear vessels (especially at the periphery of the lesions) [4–8, 11].

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Fig. 8.6  Ashy dermatosis involving the forehead in an Indian man (a). Gray-blue dots distributed around follicular/sweat glands openings are seen on dermoscopy (magnification in the inset) (b)

8.3 Melasma 8.3.1 Introduction Melasma is one of the commonest disorders of pigmentation that mainly affects females in their III–IV decades; although its exact etiology is still unknown, hormonal factors, sun exposure, and genetic predisposition are thought to play a relevant role [12, 13]. It may be seen in any skin type, although it is more common in Asians and less frequent in very light and dark phototypes [12].

8.3.2 Clinical Presentation Melasma typically manifests as progressive symmetric hyperpigmented macules/patches of the face, yet it can also affect other sun-exposed areas of the body (extrafacial melasma), such as trunk and forearms (Figs.  8.7a, 8.8 and 8.9a) [4, 5]. Two main clinicopathological subtypes do exist, namely, epidermal and dermal melasma, respectively, typified by sharp and ill-defined margins that may be better assessed with Wood’s lamp; mixed presentations are not uncommon [4, 5]. Lesions in skin of color usually present a darker hue as compared to light phototypes (Fig. 8.9a) [4, 5].

8.3.3 Dermoscopy The typical dermoscopic pattern of facial melasma regardless of skin type consists of brown structureless areas with ostial sparing (pseudonetwork) showing a focal/multifocal or, most frequently, a diffuse (as a background) distribution histologically corresponding to basal cell layer hyperpigmentation (Figs.  8.7b, 8.7, 8.8 and 8.9b) [4–8]. Focal gray structureless areas with ostial sparing and interostial brown/gray dots may also be detected and point out to a dermal pigmentary component (“dermal melasma”) [4–8]. Periosteal (follicles/eccrine sweat glands) brown pigmentation (periosteal brown circles) may also be appreciated less commonly, especially in dark phototypes (Fig. 8.9b) [4–8]. Dermoscopic examination may sometimes display telangiectasias (blurred linear branching or reticular vessels) that are either a primary vascular component (mainly in lighter skin) or the result of prolonged topical steroid application (especially in skin of color) (Fig. 8.8b) [4–8]. Besides diagnostic purposes, dermoscopy may also be of aid in choosing the optimal treatment (as the presence of vessels favors the use of a laser therapy targeting the vessels, such as pulsed dye laser), predicting therapeutic outcomes (by assessing pigment depth), and monitoring treatment (to evaluate the improvement of pigmentary and vascular findings) [4–8].

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Fig. 8.7  Melasma in a light-pigmented (phototype III) Indian woman (a). Dermoscopic assessment displays brown pseudonetwork (diffuse pigmentation with ostia sparing) with sharp margins (b)

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Fig. 8.8  Melasma in a Caucasian woman (a). Dermoscopy reveals a faint brown pigmentation with ostia sparing along with blurred linear vessels (b)

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Fig. 8.9  Melasma in an African woman (a). Dermoscopic examination shows brown pseudonetwork along with periosteal brown circles (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

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8.4 Friction Melanosis 8.4.1 Introduction Friction melanosis (FM) is a common pigmentary disease occurring due to repeated friction and persistent skin rubbing as a consequence of melanosomes squeezing into the dermis and their further engulfment by the macrophages [14, 15]. Such a condition may be seen in both fair- and dark-skinned patients, though it is more common in the latter to the higher tendency to pigmentary reaction patterns [14, 15].

8.4.2 Clinical Presentation FM is characterized by asymptomatic, rippled, or reticular, brown to black (skin of color) pigmentation over bony prom-

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inences, especially on the back, clavicles, shin, and outer aspect of forearms (Figs.  8.10a and 8.11a); facial lesions (clinically manifesting as more or less diffuse brown-black pigmentation) resulting from repeated friction have also been described, mainly in dark skin [4, 5, 14, 15].

8.4.3 Dermoscopy Dermoscopy of FM in both light and dark phototypes typically displays structureless or network-like brown areas arranged in a reticular pattern related to basal cell layer hyperpigmentation on histology (Figs. 8.10b and 8.11b) [4– 8]. Additionally, perifollicular hypopigmentation histologically corresponding to scratching-induced perifollicular acanthosis may also be observed, especially in skin of color due to the higher tendency to follicular reactions (Fig. 8.11b)

b

Fig. 8.10  Friction melanosis in a Caucasian woman (a). Brown network-like pigmentation arranged in a reticular pattern and white structureless areas are visible on dermoscopy (b)

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Fig. 8.11  Friction melanosis in a Caribbean woman (a). Dermoscopic assessment shows diffuse network-like pigmentation along with perifollicular white globular hypopigmentation (b)

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[4–8]. Further less common dermoscopic features include focal white areas (Fig.  8.10b), brown dots/globules, and white globules [4–8]. Finally, facial friction melanosis usually shows structureless brown areas with ostial sparing (brown pseudonetwork), with or without periosteal pigmentation (brown circles around follicular and eccrine sweat glands openings) [4–8].

8.5 Acanthosis Nigricans 8.5.1 Introduction Acanthosis nigricans (AN) is a common disorder characterized by asymptomatic skin pigmentation typically involving

a

the flexures which may be either idiopathic or associated with underlying disorders, especially obesity and diabetes but also malignancies or medications [16].

8.5.2 Clinical Presentation It is characterized by asymptomatic, hyperpigmented (light brown in fair-skinned patients and dark brown in skin of color) velvety plaques most frequently localized on the neck, axilla, and groin (Figs.  8.12a and 8.13a); face and acral areas (dorsal aspect of the hands) may also be involved less commonly, mainly in skin of color (Fig. 8.14a) [4, 5, 16].

b

Fig. 8.12  Acanthosis nigricans of the axilla in a Caucasian man (a). A combination of raised linear-curved structures separated by sulci (“sulci and gyri” pattern) is visible on dermoscopy; dotted vessels are also seen on the raised areas (b)

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Fig. 8.13  Acanthosis nigricans of the neck in an Indian woman (a). Dermoscopic assessment shows the so-called “sulci and gyri” pattern consisting of raised linear-curved structures separated by pigmented sulci (b)

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Fig. 8.14  Acanthosis nigricans involving the face in an Indian man (a). “Sulci and gyri” pattern and pigmented dots on raised areas are evident on dermoscopy (b)

8.5.3 Dermoscopy Dermoscopic pattern of AN consists of either a combination of raised linear-curved structures separated by sulci (“sulci and gyri” pattern) or a “cobblestone” appearance; a combination of such patterns may be observed, and both of them result from papillomatosis and hyperpigmentation of the basal layer (Figs. 8.12b, 8.13 and 8.14b) [4–8, 17]. The former pattern is more commonly observed and more marked in dark-skinned patients in which pigmentary and epidermal changes are often more pronounced (Figs.  8.13b and 8.14b) [4–8, 17]. Hyperpigmented dots over the crista cutis may also be seen in skin of color and are related to circumscribed basal layer hyperpigmentation over the tip of elongated dermal papillae on histology (Fig. 8.14b) [4–8, 17]. On the other hand, dotted vessels are seen in lighter phototypes (authors’ personal observations) (Fig. 8.12b).

8.6 Post-inflammatory Hyperpigmentation 8.6.1 Introduction Post-inflammatory hyperpigmentation (PIH) is a sequela of various skin disorders or physical/chemical injury resulting from reactive pigment production/deposition that can be epidermal (basal cell layer hyperpigmentation) or dermal (free melanin or melanophages) depending on the inciting stimulus [18]. It can occur at any age without gender predilection

and in any skin type, though it is more common in skin of color due to a higher tendency to pigmentary reaction patterns [18].

8.6.2 Clinical Presentation PIH appears as asymptomatic pigmentary macules or patches whose shape and distribution pattern vary according to the original inflammatory condition (Figs. 8.15a and 8.16a) [4, 5, 18]. The pigmentation hue differs according to the histological background, with brown to black (skin of color) lesions in case of epidermal PIH and gray-blue lesions when it comes to dermal forms [4, 5, 18].

8.6.3 Dermoscopy Dermoscopy of PIH is often unspecific but may help in differentiating it from other pigmentary disorders and determining the level of pigment that may have a prognostic value [4–6, 17]. The main findings of epidermal PIH (resulting from basal cell layer hyperpigmentation) include light to dark brown pseudonetwork (face) and either light to brown structureless or network-like areas (extra-facial areas), while brown, gray, or bluish dots typify the dermal counterpart as a result of pigment incontinence (e.g., lichen planus or discoid erythematous lupus) (Figs.  8.15b and 8.16b) [ 4–6, 17]. Overlapping aspects may be seen (especially in skin of color) (Fig.  8.16b), and in very dark phototypes, epidermal subtypes may feature a black hue due to the intense pigmenta-

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b

Fig. 8.15  Post-inflammatory hyperpigmentation in fair skin (lichen planus) (a). Dermoscopy displays small uniform brown-gray dots (b)

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Fig. 8.16  Post-inflammatory hyperpigmentation in dark skin (lichen planus) (a). Dermoscopy reveals a mixed pattern, with brown/brown-gray dots/globules over a diffuse brown background (b)

tion [4–6, 17]. Findings typical of the underlying disorder causing PIH may be seen during dermoscopy [4–6, 17].

8.7 Nevus of Ota and Becker Nevus 8.7.1 Introduction Nevus of Ota (NOO) is a dermal melanocytosis typically involving skin areas innerved by first and second branches of trigeminus that presents at birth or early childhood in most cases, yet it may develop as late as 20  years; it has ethnic predisposition and is much more common in Asians [19].

Becker nevus (BN) is a skin hamartoma generally manifesting in late childhood or early adolescence, mainly in males; androgens seem to play a role in its development with increased expression of androgen receptors being speculated to play a pathogenetic role [20].

8.7.2 Clinical Presentation NOO typically manifests as unilateral, mottled, blue-gray, or blue-brown (mainly in dark phototypes) macules involving the zygomatic and temporal areas; oral or nasal mucosa, sclera,and tympanic membrane may also be affected

8  Common Hyperpigmented Dermatoses

(Figs. 8.17a, 8.18 and 8.19a) [4, 5, 19]. Bilateral and symmetrical presentation affecting malar regions, root of nose, eyelids, and forehead may be possible (Hori’s nevus), although it usually does not involve the mucosa and has often a late onset in adulthood [4, 5, 19]. BN presents as a circumscribed hyperpigmented patch with hypertrichosis and surrounding satellite pigmented macules that mainly affect shoulder, chest, and upper trunk, though other sites like face or lower extremities may rarely be involved (Figs. 8.20a and 8.21a) [4, 5, 20]. Clinical presentation is similar in light and dark phototypes, yet pigmentation is darker in the latter (Fig. 8.21a) [4, 5, 20]. Additionally, follicular Becker’s nevus has also been reported in skin of color (Fig.  8.22a) [21], yet it may also be encountered in lighter phototype (Fig. 8.23a).

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8.7.3 Dermoscopy Dermoscopic pattern of NOO is similar in fair and dark skin and consists of brown (mainly dark phototypes) or gray/bluish structureless areas with ostial sparing (pseudonetwork) histologically resulting from accumulation of pigmented dendritic melanocytes and melanophages in papillary and reticular dermis, respectively (Figs.  8.17b, 8.18 and 8.19b) [4–7]. Pigmented pseudonetwork is also seen in melasma, but pigmentation is more inhomogeneous and may be associated with ostial obliteration in NOO (Figs.  8.17b, 8.18 and 8.19b) [4–7]. Further dermoscopic findings include brown-­ gray dots and perifollicular hypopigmentation (Fig. 8.17b) [4–7].

b

Fig. 8.17  Nevus of Ota in a Caucasian woman (a). Dermoscopic examination shows diffuse bluish pigmentation; perifollicular white halos and brown-blue pigmentation of some follicular/sweat glands ostia are also evident (b). (Courtesy of Aimilios Lallas, MD – Thessaloniki, Greece)

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Fig. 8.18  Nevus of Ota in an Indian woman (a). Dermoscopy reveals brown-blue multifocal structureless areas with obliteration of some of follicular/sweat glands openings (arrowhead) (b)

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Fig. 8.19  Darkly pigmented nevus of Ota in an Indian woman (a). Brown pseudonetwork with obliteration of some follicular/sweat glands openings (arrowhead) are seen on dermoscopy; periosteal white halos are also evident (arrow) (b). (Courtesy of Abhijeet Kumar Jha, MD – Patna, India)

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Fig. 8.20  Becker’s nevus in a Caucasian girl (a). Dermoscopic assessment displays reticular brown pigmentation with sparing of skin creases and follicular ostia (arrowhead) (b)

Dermoscopy of Becker nevus reveals pigmentary structureless or reticular areas arranged in patchy pattern histologically corresponding to basal cell layer pigmentation; shade of pigmented areas varies from light brown to dark brown in fair- and dark-skinned patients, respectively (Figs. 8.20b and 8.21b) [4–7, 22]. Terminal hairs, periosteal hypopigmentation (around hair follicles and sweat glands

openings), skin furrow hypopigmentation, and white structureless areas are other possible findings (Figs.  8.20b and 8.21b) [4–7, 22]. On the other hand, the main dermoscopic features of follicular Becker’s nevus include brown perifollicular reticular pigmentation and white perifollicular hypopigmentation in dark (Fig. 8.22b) and fair (Fig. 8.23b) phototypes, respectively (authors’ personal observations).

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Fig. 8.21  Becker’s nevus in an Indian boy (a). Dermoscopy shows reticular brown pigmentation with periosteal (hair follicles/sweat glands ostia) hypopigmentation (b)

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Fig. 8.22  Follicular Becker’s nevus in an Indian boy (a). Reticular brown pigmentation around hair follicles is seen on dermoscopy (b)

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Fig. 8.23  Follicular Becker’s nevus in a Caucasian boy (a). Dermoscopic assessment reveals perifollicular hypopigmentation (b)

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10. Nguyen K, Khachemoune A. Ashy dermatosis: a review. Dermatol Online J. 2019;25:13030. 11. Errichetti E, Angione V, Stinco G. Dermoscopy in assisting the rec1. Robles-Méndez JC, Rizo-Frías P, Herz-Ruelas ME, et  al. Lichen ognition of ashy dermatosis. JAAD Case Rep. 2017;3:482–4. planus pigmentosus and its variants: review and update. Int J 12. Kwon SH, Na JI, Choi JY, et  al. Melasma: updates and perspecDermatol. 2018;57:505–14. tives. Exp Dermatol. 2019;28:704–8. 2. Kanwar AJ, Dogra S, Handa S, et  al. A study of 124 Indian 13. Rajanala S, Maymone MB, Vashi NA.  Melasma pathogenesis: a patients with lichen planus pigmentosus. Clin Exp Dermatol. review of the latest research, pathological findings, and investiga2003;28:481–5. tional therapies. Dermatol Online J. 2019;25:10. 3. Sharma VK, Gupta V, Pahadiya P, et al. Dermoscopy and patch test- 14. Sharquie KE, Al-Dorky MK. Frictional dermal melanosis (lifa dising in patients with lichen planus pigmentosus on face: a cross-­ ease) over bony prominences. J Dermatol. 2001;28:12–5. sectional observational study in fifty Indian patients. Indian J 15. Khoo ZX, Chong JH, Koh MJA.  Davener's dermatosis. Arch Dis Dermatol Venereol Leprol. 2017;83:656–62. Child. 2019;104:1137. 4. Errichetti E, Lallas A.  Hyperpigmented dermatoses. In: Lallas A, 16. Pardeshi SS, Khemani UN, Kamath RR, et al. Therapeutic implicaErrichetti E, Ioannides D, editors. Dermoscopy in general dermations of dermoscopic findings in acanthosis nigricans: a clinical and tology. 1st ed. Boca Raton, FL: CRC; 2018. p. 106–20. histopathological study. Dermatol Ther. 2020;33:e14521. 5. Neema S. Hyperpigmented dermatoses. In: Errichetti E, Lallas A, 17. Krueger L, Saizan A, Stein JA, et  al. Dermoscopy of acquired editors. Dermoscopy in general dermatology for skin of color. 1st pigmentary disorders: a comprehensive review. Int J Dermatol. ed. Boca Raton, FL: CRC; 2021. p. 57–74. 2022;61:7–19. 6. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general 18. Davis EC, Callender VD. Post-inflammatory hyperpigmentation: a dermatology (non-neoplastic dermatoses) in skin of colour: a comreview of the epidemiology, clinical features, and treatment options parative retrospective study by the international dermoscopy sociin skin of color. J Clin Aesthet Dermatol. 2010;3:20–31. ety. Eur J Dermatol. 2020;30:688–98. 19. Chan HH, Kono T. Nevus of ota: clinical aspects and management. 7. Errichetti E, Ankad BS, Jha AK, Sonthalia S, Akay BN, Bakos R, Skinmed. 2003;2:89–96. et al. International dermoscopy society criteria for non-neoplastic 20. Kaliyadan F, Ashique KT.  Becker melanosis. In: StatPearls. dermatoses (general dermatology): validation for skin of color Treasure Island, FL: StatPearls Publishing; 2022. through a Delphi expert consensus. Int J Dermatol. 2022;61: 21. Manchanda Y, Khaitan BK, Ramam M, Das S, Al-Mutairi 461–71. N.  Follicular Becker's nevus: a new clinical variant. Indian J 8. Errichetti E, Stinco G. Dermoscopy in general dermatology: a pracDermatol. 2020;65:130–2. tical overview. Dermatol Ther. 2016;6:471–507. 22. Ingordo V, Iannazzone SS, Cusano F, Naldi L.  Dermoscopic fea9. Chang SE, Kim HW, Shin JM, et al. Clinical and histological aspect tures of congenital melanocytic nevus and Becker nevus in an of erythema dyschromicum perstans in Korea: a review of 68 cases. adult male population: an analysis with a 10-fold magnification. J Dermatol. 2015;42:1053–7. Dermatology. 2006;212:354–60.

9

Less Common Hyperpigmented Dermatoses Shekhar Neema and Enzo Errichetti

Contents 9.1 9.1.1  9.1.2  9.1.3 

Dowling-Degos Disease  Introduction  Clinical Presentation  Dermoscopy 

 112  112  112  113

9.2 9.2.1  9.2.2  9.2.3 

 acular Amyloidosis and Lichen Amyloidosis  M Introduction  Clinical Presentation  Dermoscopy 

 113  113  113  113

9.3 9.3.1  9.3.2  9.3.3 

 erra Firma-Forme Dermatosis  T Introduction  Clinical Presentation  Dermoscopy 

 116  116  117  118

9.4 9.4.1  9.4.2  9.4.3 

Dermatosis Neglecta  Introduction  Clinical Presentation  Dermoscopy 

 118  118  118  118

9.5 9.5.1  9.5.2  9.5.3 

Exogenous Ochronosis  Introduction  Clinical Presentation  Dermoscopy 

 118  118  118  119

9.6 9.6.1  9.6.2  9.6.3 

 iehl Melanosis (Pigmented Contact Dermatitis)  R Introduction  Clinical Presentation  Dermoscopy 

 120  120  120  120

9.7 9.7.1  9.7.2  9.7.3 

Gougerot-Carteaud Syndrome  Introduction  Clinical Presentation  Dermoscopy 

 121  121  121  122

References 

 123

S. Neema Department of Dermatology, Armed Forces Medical College, Pune, India E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_9

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9.1 Dowling-Degos Disease

9.1.2 Clinical Presentation

9.1.1 Introduction

The typical lesions of DDD consist of reticulated hyperpigmented macules over the flexures, such as axilla, groins, submammary folds, and neck (Figs. 9.1a and 9.2a) [1–4]. Clinical presentation is similar across the various skin types, though lesions are darker in skin of color (Figs. 9.1a and 9.2a) [1–4]. DDD is generally asymptomatic, yet pruritus may sometimes be present and aggravated by heat and friction [1–4]. Comedone-like papules, hypopigmented macules, perioral pitted scars, and palmar pits may also be seen [1–4].

Dowling-Degos disease (DDD) is an autosomal dominant genodermatosis typically arising in adult age and affecting the flexures that are mainly due to mutations in KRT5 gene, though POGLUT1 and POFUT1 genes may also be involved [1–4]. Besides classical flexural form, several variants have also been described, including generalized, follicular, genital, or associated with hidradenitis suppurativa [1–4].

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Fig. 9.1  Dowling-Degos disease in a Caucasian woman (a). Dermoscopy reveals irregular brownish projections around small, hypopigmented circles (b). (From “Dermoscopy in General Dermatology”, Lallas A, Errichetti E, Ioannides D, eds. CRC Press 2018)

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Fig. 9.2  Dowling-Degos disease in an Indian woman (a). Periosteal along with accentuated reticular pigment network is seen on dermoscopic examination (b). (From “Dermoscopy in General Dermatology for Skin of Color”, Errichetti E, Lallas A, eds. CRC Press 2021)

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9.1.3 Dermoscopy

9.2.2 Clinical Presentation

Dermoscopy of DDD may be variable, with two main patterns being reported, i.e., brown star-like area/irregular brownish projections with a hypopigmented center (mainly described in light phototypes), respectively, corresponding to elongated rete ridges with pigmentation at the tips and follicular infundibulum on histology, and brown lines configuring a “Chinese-letter,” reticular, or “star-like” pattern (mainly described in dark phototypes), resulting from basal layer pigmentation (Figs.  9.1b and 9.2b) [3–6]. On the other hand, hypopigmented macules display a white area with perifollicular pigment retention and surrounding accentuation of a reticular pigment pattern [3–6]. Additionally, pits breaking in dermatoglyphics with keratotic plugs in the center may also be seen on dermoscopy [3–6].

MA presents as asymptomatic or mildly itchy, hyperpigmented macules arranged in a rippled pattern most commonly involving the outer aspect of forearms and upper back (Figs. 9.3a and 9.4a), while LA typically manifests as either skin-colored or brown itchy papules mainly affecting the shins, though other parts of the body may be involved (Figs. 9.5a, 9.6, 9.7 and 9.8a) [3, 4, 7]. Mixed forms showing lesions of both MA and LA are possible (biphasic amyloidosis) (Fig. 9.9a) [3, 4, 7]. Some clinical variations according to skin type do exist for LA, with brown, larger, and hyperkeratotic lesions observed more commonly in darker phototypes (Fig.  9.8a) [3, 4, 7]. On the other hand, appearance of MA does not significantly differ between fair and dark skin, although lesions are generally more visible in lighter phototypes due to the more marked contrast with surrounding healthy skin (Fig. 9.3a) [3, 4, 7].

9.2 Macular Amyloidosis and Lichen Amyloidosis 9.2.1 Introduction Macular amyloidosis (MA) and lichen amyloidosis (LA) are quite common forms of primary cutaneous amyloidosis, a subtype of amyloidosis typified by skin manifestations without any systemic involvement [3, 4, 7]. Both such conditions would be related to skin scratching/friction in predisposed subjects [3, 4, 7].

a

9.2.3 Dermoscopy Dermoscopic features of MA and LA typically overlap as both of them are usually typified by a central brown or white dot/ globule (corresponding to roundish amyloid deposits in the tips of dermal papillae, with or without melanin) along with peripheral pigmentation, in the form of radiating brown streaks, dots, or circles, resulting from basal layer pigmentation or dermal free melanin/melanophages (Figs. 9.3b, 9.4, 9.5, 9.6 and 9.7b)

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Fig. 9.3  Macular amyloidosis in a Caucasian woman (a). Dermoscopic assessment shows hypopigmented white dots surrounded by brown pigmentation (better seen in the inset) (b)

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Fig. 9.4  Macular amyloidosis in a Caribbean woman (a). Dermoscopy displays brown dots surrounded by brown pigmentation that is difficult to see as it fades into the physiological pigmented background (b). (Courtesy of Maria Parodi, MD–Treviso, Italy)

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Fig. 9.5  Lichen amyloidosis in a Caucasian man (a). Dermoscopic examination reveals brown dots surrounded by brown pigmentation (better seen in the inset) (b)

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Fig. 9.6  Lichen amyloidosis in a Caucasian woman (a). Brown dots with peripheral brown striae are seen on dermoscopy (magnification in the inset) (b)

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Fig. 9.7  Hyperkeratotic lichen amyloidosis in an Indian man (a). Dermoscopy shows brown dots with peripheral brown striae (magnification in the inset) (b). (Courtesy of Soumil Khare, MD – Raipur, India)

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Fig. 9.8  Hyperkeratotic lichen amyloidosis in an Indian man (a). Central scar-like areas with peripheral brown pigmentation and white scaling are evident on dermoscopic assessment (b)

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Fig. 9.9  Biphasic skin amyloidosis in a Caucasian man (a). Dermoscopy reveals brown dots with white halos (magnification in the inset) (b). (Courtesy of Arturo Galvan, MD – Verona, Italy)

[3, 4, 8–11]. Of note, in very dark skin, peripheral pigmentation may not be so easy to detect (Fig. 9.4b) [3, 4, 8–11]. Additional, unspecific dermoscopic features that may be seen in such condition include white or brown structureless areas, brown dots/globules with or without white halos (Fig.  9.9b), white scaling (central or patchy), and broken hairs, with the last two findings being mainly found in LA [3, 4, 8–11]. Notably, scaling and bright white scar-like areas are more frequent in LA of skin of color (Fig. 9.8b) due to the higher tendency to hyperkeratosis and fibrosis, respectively [3, 4, 8–11].

9.3 Terra Firma-Forme Dermatosis 9.3.1 Introduction Terra firma-forme dermatosis (TFFD) is a quite common disorder affecting all age groups and skin types due to an abnormal or delayed keratinization causing retention of keratinocytes and melanin within the epidermis [3, 4, 12].

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9.3.2 Clinical Presentation TFFD presents as asymptomatic, hyperpigmented, velvety plaques mainly involving the creases (especially neck and armpits), though they may also commonly involve the face, trunk, and ankles (Fig.  9.10a and 9.11a) [3, 4, 12]. The diagnosis is confirmed by “wipe test,” with lesions disap-

a

pearing after rubbing with alcohol but not cleaning with soap and water, unlike dermatitis neglecta (negative “soap water swab” test) [3, 4, 12]. As for other pigmentary diseases, brown patches are more evident in lighter phototypes due to the contrast with healthy skin (Fig.  9.10a), while scaling may be more marked in skin of color (Fig. 9.11a) [3, 4, 12].

b

Fig. 9.10  Terra firma-forme dermatosis in a Caucasian man (a). Dermoscopic examination displays polygonal, plate-like brown scales arranged in a mosaic-like pattern (b)

a

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Fig. 9.11  Terra firma-forme dermatosis in an Indian man (a). The “mosaic-like” pattern consisting of regularly arranged, large polygonal, plate-­ like brown scales is seen on dermoscopy (b)

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9.3.3 Dermoscopy

9.4.3 Dermoscopy

Regardless of skin type, dermoscopy of TFFD classically reveals a pattern consisting of large polygonal, plate-like brown scales arranged in a mosaic-like pattern which is related to compact and regular orthohyperkeratosis, acanthosis, and papillomatosis along with melanin exfoliation (Figs. 9.10b and 9.11b) [3, 4, 13]. Importantly, Gougerot-­Carteaud syndrome may show a similar pattern typified by brown flat globules, yet polygonal scales seen in TFFD show a peripheral detachment which is classically lacking in the former (see Sect. 9.7) [3, 4, 13].

Dermoscopy can help in quick diagnosis of DN by revealing a peculiar pattern typified by irregularly distributed “corn-­ flake-­like” dark brown scales histologically resulting from prominent basket-weave hyperkeratosis and epidermal atrophy and irregular reduction of rete pegs (Figs.  9.12b and 9.13b) [3, 4, 13].

9.4 Dermatosis Neglecta

9.5 Exogenous Ochronosis 9.5.1 Introduction

Dermatosis neglecta (DN) is a condition due to a progressive accumulation of dirt, debris, sebum, and scales resulting from poor skin hygiene [3, 4, 13]. Cleaning with soap and water can clear the debris and reveal the diagnosis [3, 4, 13]. No racial predominance has been reported [3, 4, 13].

Exogenous ochronosis (EO) is a pigmentary dermatosis characterized by ochronotic pigment deposition in the dermis resulting from long-term application of topical hydroquinone, yet the use of topical phenol or resorcinol and systemic antimalarials (e.g., quinine) might also be involved [3, 4, 14, 15]. It is much more frequent in darker phototypes, with few cases being reported in light skin [3, 4, 14, 15].

9.4.2 Clinical Presentation

9.5.2 Clinical Presentation

DN presents as asymptomatic, hyperpigmented, velvety plaques mainly affecting areas in which the patients pay less attention to cleaning, e.g., umbilicus, around nevi, postsurgical or traumatic wound, sites of hyperalgesia, or preexisting skin conditions (Figs. 9.12a and 9.13a) [3, 4, 13].

EO is typified by symmetric hyperpigmentation in photo-­ exposed area, especially zygomatic region (Figs. 9.14a and 9.15a) [3, 4, 14, 15]. Three stages have been recognized: (I) erythema and mild hyperpigmentation; (II) caviar-like papular lesions; and (III) papulo-nodular lesions with confetti-­

9.4.1 Introduction

a

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Fig. 9.12  Dermatosis neglecta in a Caucasian woman (a). Dermoscopic assessment shows irregularly distributed “corn-flake-like” dark brown scales (b)

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Fig. 9.13  Dermatosis neglecta in an Indian boy (a). Irregularly distributed “corn-flake-like” dark brown scales are evident on dermoscopy (b)

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Fig. 9.14  Exogenous ochronosis in a fair-skinned Indian woman (phototype III) (a). Dermoscopy reveals blue or brown circles and semicircles along with linear/reticular sharp vessels (magnification in the inset) (b). (Courtesy of Vinay Keshavamurthy, MD – Chandigarh, India)

like macular depigmentation [3, 4, 14, 15]. EO often overlaps with melasma, and differentiation from worsening melasma may be troublesome [3, 4, 14, 15]. Lesions in lighter phototypes tend to be more grayish-bluish and easier to be detected due to the contrast with unaffected areas (Fig.  9.14a), whereas patches in dark skin are gray-brownish/blackish, and demarcation with healthy skin may be difficult to see (Fig. 9.15a) [3, 4, 14, 15].

9.5.3 Dermoscopy The main dermoscopic clues of EO include focal white areas (previously known as “confetti-like” depigmentation) and pigmented circles and semicircles histologically corresponding to ochronotic pigment over thickened dermal fibers arranged in a curvilinear pattern (“banana bodies”) (Figs. 9.14b and 9.15b) [3, 4, 8, 9, 16]. Other possible findings are pigmented struc-

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Fig. 9.15 Exogenous ochronosis in an African woman (a). Dermoscopic examination displays dark brown circles and semicircles, hypopigmented areas, periosteal white halos, and a few sharp linear/

reticular vessels (magnification in the inset) (b). (Courtesy of Ibrahima Traoré, MD – Conakry, Guinea)

tureless areas, globules or interostial dots, ostial obliteration, and fine telangiectasias (Figs. 9.14b and 9.15b) [3, 4, 8, 9, 16]. Of note, pigmentary structures tend to be gray, blue, or brown in phototypes III/IV and dark brown/black in phototype V/VI (Figs. 9.14b and 9.15b) [3, 4, 8, 9, 16].

9.17a); pigmentation is usually more intense in darker phototypes (Fig.  9.17a) [3, 4, 17]. Lips, thighs, and axillae may rarely be involved [3, 4, 17]. The disease is usually asymptomatic, although itching may be present in some ­ cases [3, 4, 17]. Patch tests with incriminating agents can help in confirming the diagnosis [3, 4, 17].

9.6 Riehl Melanosis (Pigmented Contact Dermatitis) 9.6.1 Introduction Riehl melanosis (RM), or pigmented contact dermatitis, is a noneczematous contact dermatitis due to repeated contact with culprit haptens causing a low-grade dermatitis that damages the basement membrane with consequent pigmentary incontinence and no spongiosis or relevant inflammation [3, 4, 17]. It is mainly due to contact with chemicals and fragrances and tends to be much more common in individuals with darker skin, especially phototypes IV/V [3, 4, 17].

9.6.2 Clinical Presentation Clinical presentation is insidious, with slowly progressive, macules/patches mostly involving the face that tends to show a brown, brown-grayish or brown-blue hue (Figs. 9.16a and

9.6.3 Dermoscopy Dermoscopy may be of particular aid in facilitating the diagnosis of RM by showing the presence of intrafollicular pigmentary dots, whose shade may vary from brown to gray (and rarely blue) based on the deepness of pigment deposit in the dermis (Figs. 9.16b and 9.17b) [3, 4, 8, 9]. This structure is related to a pigment dispersion through the follicle resulting from an appendage reaction due to trans appendage absorption of some haptens [3, 4, 8, 9]. Further dermoscopic features include perifollicular brown/gray dots, brown pseudonetwork, sparse follicular keratotic plugging, telangiectasias, and perifollicular white halo (Figs. 9.16b and 9.17b) [3, 4, 8, 9]. In skin of color, pigmentary structures tend to be more marked/ intense, whereas vessels are usually not seen (Figs. 9.17b) [3, 4, 8, 9].

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Fig. 9.16  Riehl melanosis in a fair-skinned Asiatic patient (phototype II) (a). Dermoscopy shows small brown dots, with some of them located in the follicles (arrowhead—inset), reticular vessels, and white scales/follicular plugs (b)

a

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Fig. 9.17  Riehl melanosis in an Indian woman (a). Several brown dots are visible on dermoscopic assessment, with most many of them located in the follicles (magnification in the inset) (b). (Courtesy of Vinay Keshavamurthy, MD – Chandigarh, India)

9.7 Gougerot-Carteaud Syndrome

9.7.2 Clinical Presentation

9.7.1 Introduction

From a clinical point of view, GCS presents as asymptomatic to mildly pruritic hyperpigmented macules/flat papules and plaques showing a central confluence and reticulated borders mainly affecting the trunk, although other sites may be involved (e.g., cubital folds, neck, and axillae) (Figs. 9.18a and 9.19a) [3, 4, 18, 19]. White scaling or hyperkeratosis may be seen, especially in darker phototypes (Fig. 9.19a) [3, 4, 18, 19]. Another difference according to skin type is the shade of the lesions, which darker in skin of color and may

Gougerot-Carteaud syndrome (GCS) (also known as confluent and reticulated papillomatosis) is an uncommon, acquired dermatosis due to abnormal keratinocyte differentiation [3, 4, 18, 19]. Its etiopathogenesis is still unknown, yet an abnormal host reaction to fungal (Malassezia) or bacterial agents might play a role [3, 4, 18, 19]. It is more common in females and individuals with darker skin types [3, 4, 18, 19].

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Fig. 9.18  Gougerot-Carteaud syndrome in a Caucasian boy (a). Dermoscopy displays polygonal, flat, light brown globules separated by pale striae configuring a “cobblestone” pattern (b)

a

b

Fig. 9.19  Gougerot-Carteaud syndrome in an Indian woman (a). Dermoscopic assessment shows polygonal brown globules separated by pale striae; globules are thicker than the previous Caucasian patient,

thus configuring a “crocodile skin-like” appearance (inset) (b). (Courtesy of Vinay Keshavamurthy, MD – Chandigarh, India)

feature a light brown or coral hue in fair phototypes (Figs. 9.18a and 9.19a) [3, 4, 18, 19].

pattern that is histologically related to basal layer hyperpigmentation, acanthosis, and papillomatosis (Figs.  9.18b and 9.19b) [3, 4, 8, 20]. Interestingly, in darker phototypes, such globules are thicker (giving rise to a “crocodile skin-like” appearance) or may create a more irregular pattern with sulci and gyri (“cerebriform” pattern) due to a more pronounced acanthosis and papillomatosis with disruption of the physiological skin creases (Figs. 9.19b) [3, 4, 8, 20]. White scales may also be seen as the result of hyperkeratosis [3, 4, 8, 20].

9.7.3 Dermoscopy Dermoscopic examination of GCS typically shows polygonal, flat, light brown (fair skin) to dark brown (dark skin) globules separated by pale/white striae configuring a “cobblestone”

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References 1. Rice AS, Cook C. Dowling degos disease. In: StatPearls. Treasure Island, FL: StatPearls Publishing; 2021. p. 2022. 2. Batycka-Baran A, Baran W, Hryncewicz-Gwozdz A, Burgdorf W. Dowling-degos disease: case report and review of the literature. Dermatology. 2010;220:254–8. 3. Errichetti E, Lallas A.  Hyperpigmented dermatoses. In: Lallas A, Errichetti E, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC; 2018. p. 106–20. 4. Neema S. Hyperpigmented dermatoses. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 57–74. 5. Nirmal B, Dongre AM, Khopkar US.  Dermatoscopic features of hyper and hypopigmented lesions of Dowling degos disease. Indian J Dermatol. 2016;61:125. 6. Dabas G, Mahajan R, Afra TP, et  al. Dermoscopy of follicular Dowling-Degos disease. Indian J Dermatol. 2020;65:290–4. 7. Borowicz J, Gillespie M, Miller R.  Cutaneous amyloidosis. Skinmed. 2011;9:96–100. 8. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the international dermoscopy society. Eur J Dermatol. 2020;30:688–98. 9. Errichetti E, Ankad BS, Jha AK, Sonthalia S, Akay BN, Bakos R, et al. International dermoscopy society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 10. Errichetti E, Zalaudek I, Kittler H, et  al. Standardization of dermoscopic terminology and basic dermoscopic parameters to evaluate in general dermatology (non-neoplastic dermatoses): an expert

123 consensus on behalf of the international dermoscopy society. Br J Dermatol. 2020;182:454–67. 11. Chuang YY, Lee DD, Lin CS, et al. Characteristic dermoscopic features of primary cutaneous amyloidosis: a study of 35 cases. Br J Dermatol. 2012;167:548–54. 12. Duncan WC, Tschen JA, Knox JM. Terra firma-forme dermatosis. Arch Dermatol. 1987;123:567–9. 13. Errichetti E, Stinco G. Dermoscopy in terra firma-forme dermatosis and dermatosis neglecta. Int J Dermatol. 2017;56:1481–3. 14. Simmons BJ, Griffith RD, Bray FN, Falto-Aizpurua LA, Nouri K.  Exogenous ochronosis: a comprehensive review of the diagnosis, epidemiology, causes, and treatments. Am J Clin Dermatol. 2015;16:205–12. 15. Bhattar PA, Zawar VP, Godse KV, Patil SP, Nadkarni NJ, Gautam MM. Exogenous ochronosis. Indian J Dermatol. 2015;60:537–43. 16. Khunger N, Kandhari R.  Dermoscopic criteria for differentiating exogenous ochronosis from melasma. Indian J Dermatol Venereol Leprol. 2013;79:819–21. 17. Shenoi SD, Rao R. Pigmented contact dermatitis. Indian J Dermatol Venereol Leprol. 2007;73:285–7. 18. Carlin N, Marcus L, Carlin R. Gougerot-Carteaud syndrome treated with 13-cis-retinoic acid. J Clin Aesthet Dermatol. 2010;3:56–7. 19. Davis MD, Weenig RH, Camilleri MJ.  Confluent and reticulate papillomatosis (Gougerot-Carteaud syndrome): a minocycline-­ responsive dermatosis without evidence for yeast in pathogenesis. A study of 39 patients and a proposal of diagnostic criteria. Br J Dermatol. 2006;154:287–93. 20. Errichetti E, Maione V, Stinco G. Dermatoscopy of confluent and reticulated papillomatosis (Gougerot-Carteaud syndrome). J Dtsch Dermatol Ges. 2017;15:836–8.

Common Hypopigmented Dermatoses

10

Balachandra S. Ankad, Sankappanavara V. Smitha, and Enzo Errichetti

Contents 10.1 10.1.1  10.1.2  10.1.3 

Vitiligo  Introduction  Clinical Features  Dermoscopy 

 125  125  125  128

10.2 10.2.1  10.2.2  10.2.3 

I diopathic Guttate Hypomelanosis  Introduction  Clinical Features  Dermoscopy 

 129  129  129  129

10.3 10.3.1  10.3.2  10.3.3 

Pityriasis Alba  Introduction  Clinical Features  Dermoscopy 

 132  132  132  133

10.4 10.4.1  10.4.2  10.4.3 

Post-inflammatory Hypopigmentation  Introduction  Clinical Features  Dermoscopy 

 133  133  133  133

References 

10.1 Vitiligo 10.1.1 Introduction Vitiligo is a common, acquired, depigmentary dermatosis characterized by the selective loss of melanocytes [1]. Precise underlying etiopathomechanisms are yet to be completely understood, though cytotoxic/biochemical, neural, and autoimmune factors have been speculated to play a role [1]. It affects people of any skin type, with an incidence rate

B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India S. V. Smitha MV Medical College, Bengaluru, India E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy

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of 0.5–2% worldwide, albeit some racial groups may display a higher prevalence, reaching 8.8% in Indians [1].

10.1.2 Clinical Features Vitiligo is characterized by round to oval, chalky or milky white patchy discoloration frequently showing convex margins (Figs. 10.1a, 10.2, 10.3, 10.4, 10.5 and 10.6a); hair over vitiliginous lesions may be either normal or white (leukotrichia) [1, 2]. The lesions are symptomless although itching/ burning may sometimes precede the onset [1, 2]. Face, neck, forearms, feet, dorsal hand, fingers, and sites of trauma (Koebner phenomenon) are the most commonly involved areas [1, 2]. Although clinical presentation is independent by skin type, in darker phototypes, lesions may be much more evident (Figs. 10.3a, 10.4, 10.5 and 10.6a) [1, 2]. Two main clinical variants are recognized, i.e., segmental and non-­ segmental subtypes, yet several other clinical variants have

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_10

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Fig. 10.1  Vitiligo of the leg in a Caucasian woman (a). Dermoscopy reveals bright structureless areas with sharp and convex borders (b)

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Fig. 10.2  Vitiligo of the forearm in a Caucasian man (a). Bright structureless area along with perifollicular pigmentation and a few white hairs (b)

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Fig. 10.3  Vitiligo of the leg in an Indian man (a). Dermoscopic examination shows bright structureless areas with sharp and convex borders as well as perifollicular pigmentation (b)

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Fig. 10.4  Vitiligo of the leg with evidence of Koebner phenomenon (linear lesion) in an Indian man (a). Dermoscopy displays linear bright structureless areas representing the “micro-Koebner phenomenon” (b)

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Fig. 10.5  Vitiligo of the leg with evidence of Koebner phenomenon (linear lesion) in an Indian man (a). The main bright structureless area is surrounded by satellite lesions on dermoscopy (b)

a

b

Fig. 10.6  Vitiligo of the lip in an Indian boy (a). Dermoscopy reveals bright structureless areas with sharp and convex borders; some dotted/linear vessels are also seen (b)

been reported, including trichrome, quadrichrome, pentachrome, blue, and inflammatory vitiligo [1, 2]. Vitiligo can be clinically classified as unstable or stable, with the former being typified by development of new lesions, progression of existing lesions, and the presence of Koebner phenomenon (Fig. 10.4a) and the latter showing the lack of the aforementioned findings for more than 1 year [1, 2].

10.1.3 Dermoscopy Dermoscopy of vitiligo typically shows bright structureless areas with sharp and convex borders resulting from loss of melanocytes (“diffuse white glow” pattern due to the direct reflection of light from collagen in the absence of melanin) (Figs. 10.1b, 10.2, 10.3b and 10.6b), with or without leuko-

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Fig. 10.7  Dermoscopic images of unstable lesions of vitiligo in dark phototypes: roundish white globules with extending trailing white lines giving a “comet tail-like” appearance (a) and scattered white globules with leukotrichia giving a “polka dot” pattern (b)

trichia (white hairs) and perifollicular pigmentation due to loss and sparing of hair melanocytes, respectively (Figs. 10.2b and 10.3b) [3–10]. Of note, dermoscopic pattern is r­emarkably different according to disease stage in skin of color as the presence of physiological network-like pigmentation affects dermoscopic findings of vitiligo [3– 10]. In particular, evolving/early lesions usually display a reduced pigmentary network, reversed pigmentary network, perilesional hyperpigmentation, and perifollicular pigment (albeit the last two features may also be observed in repigmenting stages) (Fig.  10.3b), while fully evolved patches feature diffuse white milky/bright background, lack of pigmentary network, and white hairs (Fig. 10.6b) [3–10]. Besides diagnostic purposes, dermoscopic assessment may also help evaluate disease stability as stable patches usually show a sharp border but also perilesional and/or perifollicular hyperpigmentation, while unstable patches are mainly typified by irregular and/or less defined borders configuring several patterns (i.e., trichrome, “starburst,” and “comet tail”), perilesional small white globules (known as satellites, confetti-like pattern, and “tapioca sago” appearance), and micro-Koebner phenomenon (i.e., white streaks over the lines of trauma around the main vitiligo lesion) (Figs. 10.4b, 10.5b, and 10.7) [3–10]. Finally, dermoscopy may help choose the most appropriate treatment (e.g., surgical treatments are usually used in stable disease) but also predict therapeutic outcomes (e.g., white hair and perifollicular pigmentation are associated with poor and good responses, respectively) and follow-up lesions during treatment (by showing an increase in perilesional and intralesional pigmentation before being seen on clinical examination) [7–12].

10.2 Idiopathic Guttate Hypomelanosis 10.2.1 Introduction Idiopathic guttate hypomelanosis (IGH) is an asymptomatic chronic hypopigmented dermatosis affecting both fair- and dark-skinned patients mainly in the elderly. It results from melanocytic loss and is thought to be related to skin aging, sun exposure, and genetic predisposition and mainly [13–15].

10.2.2 Clinical Features IGH presents as 2-mm to 2-cm, round to oval, asymptomatic, sharply demarcated porcelain-white macules with angular or irregular borders mainly involving the extremities, yet lesions of the trunk and face may be seen less commonly (Fig.  10.8a) [7, 8, 13–16]. When it affects dark-skinned patients, lesions are much more evident due to the more marked contrast with surrounding healthy skin (Figs. 10.9a and 10.10a) [7, 8, 13–16].

10.2.3 Dermoscopy The typical dermoscopic pattern of IGH consists of bright white areas with sharp margins having peripheral projections (Figs. 10.8b, 10.9 and 10.10b) [7–10, 17, 18]. Such projections are particularly evident in dark phototypes due to the optical contrast with surrounding unaffected skin and may show different morphologies, metaphorically described as “ameboid,” “petaloid,” and “feathery” pattern (Figs. 10.10b

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Fig. 10.8  Idiopathic guttate hypomelanosis of an extremely sun-­ gins (“cloudy sky-like pattern”); peripheral projections, perilesional damaged leg in a Caucasian woman (a). Dermoscopy displays a bright brown reticular pigmentation, and a few dotted/linear-curved vessels white area showing different shade of white and sharp/polycyclic mar- are also seen (b)

a

b

Fig. 10.9  Idiopathic guttate hypomelanosis of the leg in an African woman (a). Dermoscopic assessment reveals a bright white area with peripheral projections (b). (Courtesy of Nkechi A. Enechukwu, MD – Awka, Nigeria)

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Fig. 10.10  Idiopathic guttate hypomelanosis of the leg in an Indian man (a). A bright white area with peripheral projections and intralesional perieccrine brown circles (arrowhead) are evident on dermoscopy (b)

a

b

Fig. 10.11  Dermoscopic images of idiopathic guttate hypomelanosis in dark phototypes: bright white structureless area extending peripherally like petals of a flower giving rise to a “petaloid pattern” (a) and

bright white structureless area with indistinct margins giving rise to a “nebuloid pattern” (b)

and 10.11a) [7–10, 17, 18]. Of note, ill-defined margins (referred to as “nebuloid” pattern) may be seen in early lesions (Fig. 10.11b) [7–10, 17, 18]. The presence of perieccrine pigmentation is another characteristic feature of IDH in skin of color that is thought to be related to a higher resistance of perieccrine melanocytes to sun-induced damage (Fig.  10.10b) [7–10, 17, 18]. On the other hand, perilesional brown network resulting from sun-­ induced hyperpigmentation and “cloudy sky-like” pattern

(multiple small areas coalescing into irregular/polycyclic macules, with several white shades and both well- and ill-­ defined edges) are other typical findings of the disease in light phototypes (Fig.  10.8b), with the latter being mainly found in very sun-damaged skin [7–10, 17, 18]. Further less specific dermoscopic findings visible regardless of skin type include perifollicular pigmentation, intralesional brown network, and vessels (linear and/or dotted) (Figs. 10.8b and 10.9b) [7–10, 17, 18].

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10.3 Pityriasis Alba

10.3.2 Clinical Features

10.3.1 Introduction

It classically presents as depigmented macules or patches displaying ill-defined borders, though in very dark skin margins may sometimes appear sharper; fine branny scales are usually found on depigmented lesions (Figs.  10.12a and 10.13a) [7, 8, 19]. Lesions are more evident in skin of color due to the optical contrast with surrounding healthy skin (Fig. 10.13a) [7, 8, 19]. Malar and perioral areas are the commonest involved sites, though lesions may also be found over

Pityriasis alba (PA) is a common benign asymptomatic skin condition mainly observed in children typically related to atopy and xerosis; sun exposure, hot bathes, and excessive soap usage may also be favoring factors [7, 8, 19]. It affects both fair- and dark-skinned patients, though it is more prevalent in the latter [7, 8, 19].

a

b

Fig. 10.12  Extensive pityriasis alba in a Caucasian girl (a). Dermoscopy shows ill-defined dull white area with white scaling in the skin furrows (b)

a

b

Fig. 10.13  Pityriasis alba of the forearm in an Indian boy (a). Dermoscopic assessment displays ill-defined dull white area with white scaling in the skin furrows; residual intralesional pigmentation is also seen (b)

10  Common Hypopigmented Dermatoses

the arm and upper back; additionally, extensive and pigmented variants have also been described [7, 8, 19].

10.3.3 Dermoscopy Dermoscopy of PA shows dull white areas with ill-defined margins (histologically related to melanosomes loss in the basal layer of the epidermis) along with white scaling (due to hyperkeratosis) usually having an irregular/polygonal appearance or displaying a distribution in the skin furrows (Figs. 10.12b and 10.13b) [7–10, 20]. Of note, subtle light brownish pigment network is often noted in the background in dark phototypes (Fig.  10.13b) [7–10, 20]. Additionally, pigmentation in a semicircular pattern around the perieccrine openings (perieccrine semicircles) is considered to be a quite specific finding of PA in skin of color when compared to other hypopigmented dermatoses [7–10, 20]. Such a feature is thought to be related to a partial resistance to exfoliation of the melanin located around the eccrine sweat glands. Satellite white areas and brown dots may also sometimes seen in dark phototypes [7–10, 20].

10.4 Post-inflammatory Hypopigmentation 10.4.1 Introduction

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dermatological procedures [7, 8]. Although it may be observed in any skin type, it is more common and prominent in darker individuals due to heightened color contrast [7, 8].

10.4.2 Clinical Features It presents as hypopigmented or depigmented macules or patches that are usually ill-defined and irregular margins, yet well-defined lesions may sometimes be observed [7, 8]. The size and shape typically follow the pattern of original inflammatory dermatoses or causative injury (Figs. 10.14a, 10.15 and 10.16a) [7, 8]. The degree of whitening varies from partial to total loss of pigment, while surface may be smooth or scaly [7, 8].

10.4.3 Dermoscopy Dermoscopy of PIH usually reveals just unspecific features, i.e., ill-defined white background histologically related to a decrease in epidermal melanin, yet dermoscopic features of the original inflammatory lesions may be seen, thus supporting the retrospective diagnosis [7, 8]. Possible differences according to the skin type depends on the causative dermatosis. Some examples of PIH are shown in Fig. 10.14b, 10.15 and 10.16b [7, 8].

Post-inflammatory hypopigmentation (PIH) is a commonly encountered cause of acquired hypopigmentation; it can be secondary to cutaneous inflammation, injury, or

a

b

Fig. 10.14  Post-inflammatory hypopigmentation due to discoid lupus erythematosus in a Caucasian man (a). Dermoscopy reveals an ill-defined bright white area with remnants of the original dermatosis, i.e., follicular plugs and linear-curved vessels (magnification in the inset) (b)

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Fig. 10.15  Post-inflammatory hypopigmentation due to psoriasis in an African girl (a). Dermoscopy shows an ill-defined bright white area with remnants of the original dermatosis, i.e., uniform dotted vessels (b)

a

b

Fig. 10.16  Post-inflammatory hypopigmentation due to pityriasis lichenoides chronica in an Indian male (a). Dermoscopy displays an ill-defined bright white area with remnants of the original dermatosis, i.e., orange-brown area (b) 6. Thatte SS, Khopkar US. The utility of dermoscopy in the diagnosis of evolving lesions of vitiligo. Indian J Dermatol Venereol Leprol. 2014;80:505–8. 7. Errichetti E, Lallas A, Ioannides D. Hypopigmented disorders. In: 1. Bergqvist C, Ezzedine K.  Vitiligo: a review. Dermatology. Errichetti E, Lallas A, Ioannides D, editors. Dermoscopy in general 2020;236:571–92. dermatology. 1st ed. Boca Raton, FL: CRC Press; 2019. p. 257–69. 2. Sehgal VN, Srivastava G.  Vitiligo: compendium of clinico-­ 8. Neema S.  Hypopigmented dermatoses. In: Errichetti E, Lallas A, epidemiological features. Indian J Dermatol Venereol Leprol. editors. Dermoscopy in general dermatology for skin of color. 1st 2007;73:149–56. ed. Boca Raton, FL: CRC; 2021. p. 75–84. 3. Vinay K, Ankad BS. Dermoscopic features of pigmentary diseases 9. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general in ethnic skin. Indian Dermatol Online J. 2021;12:24–33. dermatology (non-neoplastic dermatoses) in skin of colour: a com4. Ankad BS, Koti VR.  Dermoscopic approach to hypopigmenparative retrospective study by the international dermoscopy socitary or depigmentary lesions in skin of color. Clin Dermatol Rev. ety. Eur J Dermatol. 2020;30:688–98. 2020;4:79–83. 10. Errichetti E, Ankad BS, Jha AK, et  al. International dermoscopy 5. Kumar Jha A, Sonthalia S, Lallas A, Chaudry RKP.  Dermoscopy society criteria for non-neoplastic dermatoses (general dermatolin vitiligo: diagnosis and beyond. Int J Dermatol. 2018;47:50–4.

References

10  Common Hypopigmented Dermatoses ogy): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71. 11. Nirmal B, Antonisamy B, Peter CVD, George L, George AA, Dinesh GM.  Cross-sectional study of dermatoscopic findings in relation to activity in vitiligo: BPLeFoSK criteria for stability. J Cutan Aesthet Surg. 2019;12:36–41. 12. Errichetti E, Zelin E, Pinzani C, Kyrgidis A, Lallas A, Stinco G.  Dermoscopic and clinical response predictor factors in nonsegmental vitiligo treated with narrowband ultraviolet B phototherapy: a prospective observational study. Dermatol Ther. 2020;10:1089–98. 13. Kakepis M, Havaki S, Katoulis A, Katsambas A, Stavrianeas N, Troupis TG. Idiopathic guttate hypomelanosis: an electron microscopy study. J Eur Acad Dermatol Venereol. 2015;29:1435–8. 14. Bulat V, Situm M, Maricic G, et al. Idiopathic guttate hypomelanosis: a comprehensive overview. J Pigment Disord. 2014;1:150.

135 15. Kim SK, Kim EH, Kang HY, Lee ES, Sohn S, Kim YC.  Comprehensive understanding of idiopathic guttate hypomelanosis: clinical and histopathological correlation. Int J ­ Dermatol. 2010;49:162–6. 16. Poddar I, Sarkar R. Idiopathic guttate hypomelanosis: an overview. Pigment Int. 2018;5:83–90. 17. Ankad BS, Beergouder SL. Dermoscopic evaluation of idiopathic guttate hypomelanosis: a preliminary observation. Ind Dermatol Online J. 2015;6:164–7. 18. Errichetti E, Stinco G. Dermoscopy of idiopathic guttate hypomelanosis. J Dermatol. 2015;42:1118–9. 19. Lin RL, Janniger CK. Pityriasis alba. Cutis. 2005;76:21–4. 20. Ankad BS, Smitha VS, Errichetti E, Rangappa M. Facial pityriasis alba, polymorphous light eruption, and vitiligo in children: a dermoscopic distinction. J Ski Stem Cell. 2021;8:e121848.

Less Common Hypopigmented Disorders

11

Balachandra S. Ankad, Shibani Bhatia, and Enzo Errichetti

Contents 11.1 11.1.1  11.1.2  11.1.3 

 rogressive Macular Hypomelanosis  P Introduction  Clinical Features  Dermoscopy 

 137  137  137  138

11.2 11.2.1  11.2.2  11.2.3 

 chromic Nevus and Hypomelanosis of Ito  A Introduction  Clinical Features  Dermoscopy 

 138  138  139  139

11.3 11.3.1  11.3.2  11.3.3 

Ash-Leaf Macules  Introduction  Clinical Features  Dermoscopy 

 141  141  141  141

11.4 11.4.1  11.4.2  11.4.3 

Hypopigmented Leprosy  Introduction  Clinical Features  Dermoscopy 

 142  142  142  142

References 

11.1 Progressive Macular Hypomelanosis 11.1.1 Introduction Progressive macular hypomelanosis (PMH) is an underdiagnosed condition usually occurring on the trunk of adolescents and young adults [1]. It was originally described in dark-skinned patients, but now it is known to have a worldwide distribution affecting a variety of skin types. The pathogenesis of PMH has found to have some correlation with predominance of Propionibacterium acnes, which has been B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India S. Bhatia Kaya Skin Clinic, Mumbai, India E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy

 143

found in abundance in the pilosebaceous units of lesional skin [1–3].

11.1.2 Clinical Features PMH clinically manifests as asymptomatic, symmetric, ill-­ defined, and non-scaly hypopigmented macules which coalesce into large patches that may cause extensive hypopigmentation with some islands of spared skin (Figs. 11.1a and 11.2a) [1–3]. Lesions are concentrated in areas with high sebaceous gland density (i.e., back and abdomen) and are more visible in skin of color due to the optical contrast with unaffected skin (Fig. 11.1a) [1–3]. Clinical diagnosis is supported by the presence of a red follicular fluorescence on Wood light examination due P. acnes colonization. The course of the disease is variable, and it can resolve on its own in 3–5 years [1–4].

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_11

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b

Fig. 11.1  Progressive macular hypomelanosis in an Indian man (a). Dermoscopy shows ill-defined hypopigmented areas with no scales (b)

a

b

Fig. 11.2  Progressive macular hypomelanosis in an Indian man (a). Dermoscopic examination reveals ill-defined hypopigmented areas with no scales (b)

11.1.3 Dermoscopy Dermoscopy of PMH shows only nonspecific findings, i.e., illdefined hypopigmented areas histologically correlating with reduced melanin with normal melanocyte number (Figs. 11.1b and 11.2b) [2–4]. Subtle residual uniform reticular pigmentation can be noticed in skin of color as depigmentation is not complete (Fig. 11.1b) [2–4]. However, the main dermoscopic clue of PMH is the lack of scaling that may help differentiate such a condition from its main differential diagnoses, including pityriasis versicolor and pityriasis alba, as both of them are typified by white scales (perifollicular and in skin furrows in the former and irregular or polygonal in the latter) [2–4].

11.2 Achromic Nevus and Hypomelanosis of Ito 11.2.1 Introduction Achromic nevus (AN) and hypomelanosis of Ito (HOI) are hypopigmentary disorders considered to be genetic cutaneous mosaicisms that are usually present at birth, but they can also become evident during childhood [2, 3]. HOI can be associated with neurological and musculoskeletal abnormalities. Both of them may be seen in any skin type [2, 3].

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11.2.2 Clinical Features AN manifests as an asymptomatic white patch with sharp and serrated borders which is often surrounded by satellite white macules, thus giving rise to a “splash of paint”-like aspect (Figs.  11.3a and 11.4a) [2–4]. It is usually seen on trunk but can also occur on the limbs or elsewhere; clinical variants include segmental, linear, and systematized [2–4]. On the other hand, HOI presents as asymmetric streaky, patchy, whorl-like, or linear hypopigmented patches following Blaschko lines and usually occurring on the trunk, yet lesions can also be seen on the extremities (Figs. 11.5a and 11.6a) [2–4]. It may be associated with CNS, eye, and bone abnormalities [2–4].

a

Clinical presentation of both such conditions is similar between dark and light phototypes, though they are more noticeable in the former [2–4].

11.2.3 Dermoscopy AN and HOI feature a similar pattern on dermoscopy, i.e., depigmented structureless areas displaying a bright white or dull white (more frequently) shade and sharp- (more frequently) or ill-defined, irregular (serrated with irregular “pseudopods”) margins (Figs. 11.3b, 11.4, 11.5 and 11.6b) [2–6]. Importantly, the hue of the white background and sharpness of the borders may vary in the context of the

b

Fig. 11.3  Achromic nevus in an Indian male (a). Dermoscopy displays dull white area with serrated/ill-defined margins and intralesional brown islands of pigmentation and perifollicular pigmentation (b)

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b

Fig. 11.4  Achromic nevus in a Caucasian girl (a). A dull white area with ill-defined margins is seen on dermoscopy; subtle intralesional brown islands are also evident (arrowhead) (b)

a

b

Fig. 11.5  Hypomelanosis of Ito in an Indian boy (a). Dermoscopic assessment shows ill-defined dull white areas with intralesional residual pigmentation and periosteal pigmentation (arrowhead) (b)

lesion, unlike vitiligo, according to the level of melanin content reduction [2–6]; hairs are usually pigmented (Figs. 11.3b, 11.4 and 11.5b) [2–6]. However, the main dermoscopic clue of both AN and HOI is represented by the presence of intralesional “islands of spared skin,” especially located in proximity of the lesion periphery (Figs. 11.3b, 11.4, 11.5 and 11.6b) [2–6].

Such areas are usually seen as brown structureless areas in fair-­skinned patients and as brown network in skin of color [2–6]. Additionally, perifollicular and perieccrine pigmentation may be visible, especially in darker phototypes (Figs. 11.3b and 11.5b) [2–6]. Such differences are due to the physiological more pronounced pigment background in dark skin [2–6].

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a

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b

Fig. 11.6  Hypomelanosis of Ito in a Caucasian girl (a). Dermoscopy reveals ill-defined dull white globular areas intermingled with residual pigmentation (b)

11.3 Ash-Leaf Macules 11.3.1 Introduction Ash-leaf macules (ALMs) are depigmented macules that may be observed in general population without any pathological significance [2, 3, 7]. However, when the number is more than two, their presence is considered to be a major (and early) diagnostic criterion of tuberous sclerosis [2, 3, 7].

11.3.2 Clinical Features ALMs manifest as elongated, depigmented, or off-white patches generally measuring 1–3 cm typically resembling a leaf of eastern mountain ash tree [2, 3, 7]; they generally

present with one tapered and one rounded end (Figs. 11.7a and 11.8a) [2, 3, 7]. Clinical appearance is independent by skin phototype, though they are usually more evident in skin of color [2, 3, 7].

11.3.3 Dermoscopy Dermoscopy of ALMs shows a dull white background showing ill- (more commonly) or well-defined irregular margins (Figs. 11.7b and 11.8b) [2, 3]. Subtle intralesional pigmented areas representing “islands of sparing” may sometimes be seen as brown structureless (fair skin) or reticular (dark skin) areas, yet they are less common compared to AN and HOI [2, 3]. Additionally, peripheral pseudopods and perifollicular or perieccrine pigment are usually not noted in ALMs [2, 3].

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b

Fig. 11.7  Ash-leaf macule in an Indian boy (a). Dermoscopic examination shows a dull white background showing ill-defined irregular margins (b)

a

b

Fig. 11.8  Ash-leaf macule in a Caucasian girl (a). An ill-defined dull white background is seen on dermoscopy (b)

11.4 Hypopigmented Leprosy 11.4.1 Introduction Leprosy, also known as Hansen’s disease, is a chronic granulomatous disorder caused by Mycobacterium leprae that mainly affects the nerves and skin [2, 3]. Lesions may display several clinical patterns, including hypopigmented patches, especially borderline tuberculoid and indeterminate leprosy [2, 3].

11.4.2 Clinical Features Hypopigmented lepromatous lesions classically present as one or multiple ill-defined hypopigmented macules or

patches typified by hypo- or anesthesia that may be mistaken for other frequent hypopigmented dermatoses (Figs.  11.9a and 11.10a) [2, 3]. Hypopigmented lesions are much more visible in darker phototypes as they may be quite subtle in lighter skin (Fig. 11.9a) [2, 3].

11.4.3 Dermoscopy Dermoscopic pattern of hypopigmented leprosy consists of an ill-defined, dull white background (histologically related to decreased melanocytes) often containing distorted intralesional brown reticular areas and periosteal (perifollicular/perieccrine) pigmentation (“spared” areas) (Figs. 11.9b and 11.10b) [2, 3, 8–12]. However, the main

11  Less Common Hypopigmented Disorders

a

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b

Fig. 11.9  Hypopigmented lepromatous lesions in an Indian male (a). Dermoscopy displays distorted pigment network, focal ill-defined dull white areas, circle hair, and decreased eccrine openings (appearing as white dots) (b)

a

b

Fig. 11.10  Hypopigmented leprosy in fair skin (a); dermoscopy shows an ill-defined dull white area with reduction of hairs (b)

dermoscopic clue of this clinical variant of leprosy is represented by the reduction of the appendageal structures in the absence of fibrosis/ulceration resulting from granulomatous destruction of hairs and sweat glands [2, 3, 8–12]. This finding is evident on dermoscopy as a loss of hairs and sweat gland ostia (white dots), with the latter being more evident in darker skin types (Figs. 11.9b and 11.10b) [2, 3, 8–12]. Additional dermoscopic features include circle-like and broken hairs as well as widening of skin cleavage lines (better visible in darker phototypes) [2, 3, 8–12].

References 1. Desai SR, Owen JL.  Progressive macular hypomelanosis: an update. Pigment Int. 2014;1:52–5. 2. Errichetti E, Lallas A, Ioannides D. Hypopigmented disorders. In: Errichetti E, Lallas A, Ioannides D, editors. Dermoscopy in general dermatology. 1st ed. Boca Raton, FL: CRC Press; 2019. p. 257–69. 3. Neema S.  Hypopigmented dermatoses. In: Errichetti E, Lallas A, editors. Dermoscopy in general dermatology for skin of color. 1st ed. Boca Raton, FL: CRC; 2021. p. 75–84. 4. Ankad BS, Koti VR.  Dermoscopic approach to hypopigmentary or depigmentary lesions in skin of color. Clin Dermatol Rev. 2020;4:79–83.

144 5. Malakar S, Ranglani H, Malakar S.  Dermoscopic features of congenital hypopigmentary disorders. Our Dermatol Online. 2021;12:e19. 6. Vinay K, Ankad BS.  Dermatoscopic features of pigmentary diseases in ethnic skin. Indian Dermatol Online J. 2021;12:24–33. 7. Jindal R, Jain A, Gupta A, Shirazi N.  Ash-leaf spots or naevus depigmentosus: a diagnostic challenge. BMJ Case Rep. 2013;2013:bcr2012007008. 8. Bhatia AS, Badad A, Hogade AS, Spoorthy M. Dermatoscopy and clinicopathological correlation in different spectrum of leprosy. Clin Dermatol Rev. 2021;5:65–70. 9. Vinay K, Kamat D, Chatterjee D, Narang T, Dogra S. Dermatoscopy in leprosy and its correlation with clinical spectrum and histopa-

B. S. Ankad et al. thology: a prospective observational study. J Eur Acad Dermatol Venereol. 2019;33:1947–51. 10. Ankad BS, Sakhare PS. Dermoscopy of borderline tuberculoid leprosy. Int J Dermatol. 2018;57:74–6. 11. Errichetti E, Ankad BS, Sonthalia S, et al. Dermoscopy in general dermatology (non-neoplastic dermatoses) in skin of colour: a comparative retrospective study by the international dermoscopy society. Eur J Dermatol. 2020;30:688–98. 12. Errichetti E, Ankad BS, Jha AK, Sonthalia S, Akay BN, Bakos R, et al. International dermoscopy society criteria for non-neoplastic dermatoses (general dermatology): validation for skin of color through a Delphi expert consensus. Int J Dermatol. 2022;61:461–71.

Infiltrative Dermatoses

12

Enzo Errichetti, Balachandra S. Ankad, Soumil Khare, Biswanath Behera, and Payal Chauhan

Contents 12.1 12.1.1  12.1.2  12.1.3 

Mastocytosis  Introduction  Clinical Presentation  Dermoscopy 

 145  145  146  148

12.2 12.2.1  12.2.2  12.2.3 

Cutaneous Xanthomas  Introduction  Clinical Presentation  Dermoscopy 

 149  149  149  149

12.3 12.3.1  12.3.2  12.3.3 

Xanthogranuloma  Introduction  Clinical Presentation  Dermoscopy 

 153  153  153  153

12.4 12.4.1  12.4.2  12.4.3 

 rimary Cutaneous Lymphomas  P Introduction  Clinical Presentation  Dermoscopy 

 155  155  155  156

References 

 161

12.1 Mastocytosis E. Errichetti (*) Department of Medical Area, Institute of Dermatology, University of Udine, Udine, Italy B. S. Ankad Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India S. Khare BRLSABVM Govt. Medical College and Hospital, Rajnandgaon, Chhattisgarh, India B. Behera Department of Dermatology, and Venereology, AIIMS, Bhubaneswar, India

12.1.1 Introduction The term mastocytosis includes a group of conditions characterized by mast cell proliferation and accumulation in one or more organs, with the skin being the most frequently involved site [1–3]. Three main clinical subtypes do exist, i.e., maculopapular cutaneous mastocytosis (including urticaria pigmentosa [UP] and telangiectasia macularis eruptiva perstans [TMEP]), diffuse cutaneous mastocytosis, and mastocytoma [1–3]. All these conditions are pretty uncommon in very dark phototypes, especially TMEP [1–3].

P. Chauhan Department of Dermatology, Venereology and Leprosy, Himalayan Institute of Medical Sciences, Swami Rama Himalayan University, Dehradun, India

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 E. Errichetti et al. (eds.), Clinical and Dermoscopic Atlas of Non-Neoplastic Dermatoses, https://doi.org/10.1007/978-3-031-19688-1_12

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12.1.2 Clinical Presentation UP manifests as either red-brown (fair skin) or brown (especially dark skin) maculae, papules, nodules, and/or plaques that are commonly larger and more infiltrated in pediatric population than adults (Figs.  12.1a, 12.2 and 12.3a); if lesions are rubbed, they may become erythematous/edematous (Darier’s sign) [1–3]. TMEP is characterized by erythematous (fair skin) or brown-reddish (dark a

skin) macules often showing irregular margins and a diameter