Clinical Dermatology Review

SYMPOSIUM: BASICS OF DERMOSCOPY AND DERMOSCOPIC PATTERNS
Year
: 2020  |  Volume : 4  |  Issue : 2  |  Page : 74--78

Dermoscopic approach to inflammatory lesions in skin of color


Balachandra S Ankad, Varsha R Koti 
 Department of Dermatology, S Nijalingappa Medical College, Bagalkot, Karnataka, India

Correspondence Address:
Balachandra S Ankad
Department of Dermatology, S. Nijalingappa Medical College, Navanagar, Bagalkot - 587 102, Karnataka
India

Abstract

Introduction: Dermoscopy is an in vivo and non-invasive tool that assists as an adjunctive method in the diagnosis of many dermatoses. Dermoscopic studies and research in the field of inflammatory and infective lesions are limited to case series or case reports without definitive criteria. Authors have attempted to describe a very basic approach to dermoscopic diagnosis of inflammatory conditions like psoriasis, eczema, lichen planus, pityriasis rosea, prurigo nodularis, and discoid lupus erythematosus. Aim: To propose basic dermoscopic guidelines in terms of approach to an inflammatory lesion.Summary: Dermoscopy of inflammatory conditions is referred to as 'inflammoscopy'. Basic approach in inflammoscopy is based on 5 dermoscopic parameters which include; i) background colour, ii) vessels, iii) scales, iv) follicular findings and v) specific clues. Dermoscopy helps in the differentiation of many inflammatory lesions by demonstrating characteristic patterns thus aiding in its diagnosis. Uniform and regular dotted vessels are seen in psoriasis. Wickham striae, adherent fabric fibre sign, yellow clod sign and white rosettes are respectively a special clue for the diagnosis of lichen planus, prurigo nodularis, eczema and early DLE lesion. Collarette scales over brownish yellow background are seen in P. rosea. Dermatologist dealing with skin lesions in patients with skin types IV, V, and VI should be aware that there are slight variations in the dermoscopic pattern owing to amount of melanin.



How to cite this article:
Ankad BS, Koti VR. Dermoscopic approach to inflammatory lesions in skin of color.Clin Dermatol Rev 2020;4:74-78


How to cite this URL:
Ankad BS, Koti VR. Dermoscopic approach to inflammatory lesions in skin of color. Clin Dermatol Rev [serial online] 2020 [cited 2020 Sep 21 ];4:74-78
Available from: http://www.cdriadvlkn.org/text.asp?2020/4/2/74/292482


Full Text



 Introduction



Dermoscopy is an in vivo and noninvasive tool that assists as an adjunctive method in the diagnosis of many dermatoses including neoplastic and nonneoplastic lesions and its role is well established with specific criteria for diagnosis in melanoma, basal cell carcinoma, seborrheic keratosis, and keratinizing tumors such as squamous cell carcinoma and keratoacanthoma. However, dermoscopic studies and research in the field of inflammatory and infective lesions are limited to case series or case reports without definitive criteria. To prevent a conflict regarding the same, the International Dermoscopy Society has proposed a consensus of dermoscopy in inflammatory conditions as a basic guide.[1] Although many case studies, case series, and observational descriptions of dermoscopy in nonneoplastic pigmentary lesions are reported in the literature, criteria for these conditions are not yet described.

Here, the authors have attempted to describe a very basic approach to the dermoscopic diagnosis of inflammatory (psoriasis [PS], eczema, lichen planus [LP], pityriasis rosea [PR], prurigo nodularis [PN], and discoid lupus erythematosus [DLE]).

PS, eczema, LP, PR, PN, and DLE are the major crunch of inflammatory conditions in routine dermatological practice. With classical clinical features, diagnosis is not a problem in these diseases. However, it becomes challenging when two conditions overlap or in atypical manifestations. Dermoscopy of inflammatory conditions is referred to as “inflammoscopy.” Basic approach in inflammoscopy is mainly based on the five dermoscopic parameters which include: (i) background color, (ii) vessels (including morphology and distribution), (iii) scales (including color and distribution), (iv) follicular findings, and (v) specific clues.[2] It is noteworthy that “pigment pattern” as an additional parameter may be included, which may reveal pigment dots or globules and their color, morphology, and distribution. Importantly, the absence of typical pigment network or pigmentation in few inflammatory conditions is an added feature for diagnosis.

 Psoriasis



Dermoscopy in PS reveals pinkish background, diffuse bright-white scales, and regular dotted vessels in homogeneous pattern [Figure 1]a which correlate to inflammation in the upper dermis, hyper- and parakeratosis, and tips of the dilated, elongated papillary loops on histopathology, respectively.[3] It should be noted that scales are bright white and diffuse. No follicular structures are involved in PS; hence, dermoscopy does not demonstrate patterns related to follicles. Rarely, dermoscopy shows glomerular vessels which, if present, are highly specific to PS and are better visualized at higher magnifications of dermoscope. Glomerular vessels are twisted vessels and resemble the glomerular apparatus of a kidney.[4] Hence, in line with basic guidelines, background is pinkish or reddish color, vasculature is uniform dotted vessels, and scales are bright white. No pigment network or no follicular structures are seen in PS.{Figure 1}

 Lichen Planus



LP shows a plethora of patterns in dermoscopy. Background color is blue or purple and white scales can be seen in the center or periphery of the lesion. Scales are dull white. Dotted and linear vessels are, respectively, noted in the center and periphery [Figure 1]b. Follicular structures are unaffected in classical LP. However, hypertrophic LP (HLP) and follicular LP show changes in the follicles in the form of dilated follicles with plugs which are named “corn pearls,” and they are white or yellow in color [Figure 1]c. In few instances, follicular plugs appear as yellow globules and are located in entire lesions diffusely.[5] The characteristic feature of LP is pearly white or bluish-white strands which may cover entire lesion or arranged in different shapes.[6] These structures are termed as Wickham striae and are considered as a special clue. In pigment pattern, black dots that are arranged in different patterns are seen most commonly in regressing lesions of LP and in hypertrophic lesions. Blue-gray globules which suggest of melanophages are characteristically seen in HLP.[6]

Thus, according to basic guidelines, background is bluish-white or purplish color, vasculature is dotted or linear vessels, scales are dull white, pigment pattern is black or blue-gray globules, and follicular structures are comedo-like openings (only in HLP and follicular variants of LP). Wickham striae are considered as a special clue in LP.

 Prurigo Nodularis



Dermoscopic patterns in PN vary in acute excoriated and chronic hyperkeratotic stages. In the former, yellowish or reddish-brown crusts surrounded by pearly white area and red dots and globules [Figure 1]d are seen, whereas in the latter, pearly white areas form the main pattern with similar vascular structures [Figure 1]e. Pearly white areas extending to periphery appear as “starburst” pattern.[7] Peripheral brownish striations are seen in both the variants [Figure 1]d and e].[5] In accordance with basic dermoscopic parameters, background colour is white and vascular structures are dotted or globular vessels. Brown striations at periphery constitute pigment pattern and scales are white which are located mainly at periphery. Follicular changes are minimal in PN and are specifically seen in hyperkeratotic lesions of long duration.[7] Due to excoriation and microulceration, fabric fibers are adhered to the surface of lesions. This is called “adherent fabric fiber” sign which is a crucial sign of ulcerative malignant lesions or malignant transformation of benign lesions.[8] However, we believe this is a special clue for the diagnosis of PN because this sign is not seen in HLP or lichen simplex chronicus which appears similar clinically.

 Pityriasis Rosea



Dermoscopy of PR demonstrates two characteristic patterns, namely collarette white scales and yellowish background.[9] However, in skin of color, background appears brownish-yellow rather than clear yellow [Figure 2]a. Both herald and daughter patches show identical dermoscopic features.[9],[10] In terms of dermoscopic parameter, background color is brownish- yellow, scales are white and arranged in a collarette fashion, vessels are dotted and situated at periphery, no changes in follicular structures and with no special clue. Brown dots located at periphery of lesion are considered as a pigment pattern in PR suggestive of hemosiderin deposition. It is noteworthy that vascular structures are difficult to appreciate in darker skin types. When observed, they not as regular as in PS and are located at the periphery.[2],[10]{Figure 2}

 Eczema (Dermatitis)



Morphologically eczema is divided into acute, subacute, and chronic based on the time of presentation. While dermoscopic patterns vary in different stages of eczema, generally red dots, yellow serocrust, and focal dull-white scales are peculiarly seen in all stages [Figure 2]b, [Figure 2]c, [Figure 2]d.[9] It should be noted that brownish-yellow crusts are observed in skin of color instead of yellow crusts. Background color is pinkish-yellow to brownish-yellow, vessels are in cluster pattern, scales are yellowish-brown. No changes in the follicular structures and pigmentation as well.[10],[11] Yellow serocrust is termed as “yellow clod” sign, and we believe that this is a special clue in eczema. Scaling is patchy or absent and background color is white in subacute and chronic stages of eczema.[9],[10],[11] “Adherent fabric fiber” sign is also seen in eczema.

 Discoid Lupus Erythematosus



Dermoscopic patterns in DLE differ in stages of lesions which include follicular keratotic plugging, telangiectasia, perifollicular red dots, perifollicular white halo, and white scales in acute inflammatory stage [Figure 2]e, whereas with white structureless areas, telangiectasia, dotted vessels, and blue-gray globules are observed in late stage [Figure 1]f.[12] Pinkish-white background, telangiectasia, white scales, blue-gray globules, and yellow or white follicular keratotic plugs are dermoscopic patterns in terms of background, vascular, scales, pigment pattern, and follicular changes, respectively. Perilesional blackish hyperpigmentation is another feature of pigment pattern. It is important to note that hyperkeratosis of dilated infundibulum appears as four white tiny strands coming together to make a circle under polarized lights. This is termed as “white rosettes.” While white rosettes are seen in many cancerous and infective conditions, with all probability, DLE is the only disease which shows rosettes among the other inflammatory lesions. We think it is a special clue for DLE.[13]

To conclude, dermoscopy helps in the differentiation of many inflammatory lesions by demonstrating characteristic patterns. Few dermatoses show peculiar specific patterns and special clue as well [Table 1]. Dermatologists dealing with skin lesions in patients with skin Types IV, V, and VI should be aware that there are slight variations in the dermoscopic pattern owing to the amount of melanin. It definitely reduces the number of differentials of a given inflammatory lesion in clinical practice of dermatology.{Table 1}

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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