Accuracy of Dermoscopic Criteria for the Diagnosis of Psoriasis, Dermatitis, Lichen Planus and Pityriasis Rosea

A. Lallas; A. Kyrgidis; T.G. Tzellos; Z. Apalla; E. Karakyriou; A. Karatolias; I. Lefaki; E. Sotiriou; D. Ioannides; G. Argenziano; I. Zalaudek


The British Journal of Dermatology. 2012;166(6):1198-1205. 

In This Article

Abstract and Introduction


Background Dermoscopy is useful in evaluating skin tumours, but its applicability extends also to the field of inflammatory skin disorders. Plaque psoriasis (PP), dermatitis, lichen planus (LP) and pityriasis rosea (PR) are common inflammatory skin diseases, but little is currently known about their dermoscopic features.
Objectives To determine and compare the dermoscopic patterns associated with PP, dermatitis, LP and PR and to assess the validity of certain dermoscopic criteria in the diagnosis of PP.
Methods Patients with PP, dermatitis, LP and PR were prospectively enrolled. The single most recently developed lesion was examined dermoscopically and histopathologically. Variables included vascular morphology, vascular arrangement, background colour, scale colour, scale distribution and presence of Wickham striae. Univariate and adjusted odds ratios were calculated. Discriminant functions were used to plot receiver-operator characteristic curves.
Results Eighty-three patients with PP and 86 patients with either dermatitis, LP or PR were included in the study. Dotted vessels in a regular arrangement over a light red background and white scales were highly predictive for the diagnosis of PP, whereas dermatitis more commonly showed yellow scales and dotted vessels in a patchy arrangement. PR was characterized by yellowish background, dotted vessels and peripheral scales; whitish lines (Wickham striae) were seen exclusively in LP.
Conclusions PP, LP, PR and dermatitis show specific dermoscopic patterns that may aid their clinical diagnosis. Certain combinations of dermoscopic features can reliably predict the diagnosis of PP.


Plaque psoriasis (PP), dermatitis, pityriasis rosea (PR) and lichen planus (LP) are common inflammatory skin diseases. Their characteristic appearance allows a clinical diagnosis in a high proportion of patients.[1–4] However, unusual presentations at times do exist and may cause difficulties in the differentiation among these entities.[1–4] In those cases, histopathology contributes significantly to the accurate diagnosis.[5]

Dermoscopy as a noninvasive tool has become standard in the preoperative evaluation of skin tumours.[6] Thereby dermoscopy offers the benefit to assess pigmented and vascular structures that are not visible clinically.

Particularly the improved visualization of vessels, but also colour variegations that are difficult to recognize with the naked eye, explain why dermoscopy is gaining increasing importance in the diagnosis of skin lesions in general dermatology: today dermoscopy is used in the realm of skin infections and infestations (entomodermoscopy), hair and scalp disorders (trichoscopy), nailfold capillary abnormalities (capillaroscopy) and inflammatory skin disorders.[7]

Dermoscopic patterns of red dots or globules arranged in a homogeneous, regular or ring-like fashion have been described as common findings in PP.[8–10] However, there are limited data available concerning the dermoscopic pattern of dermatitis, PR and LP; moreover, sporadic cases of dermatitis reportedly show dermoscopic patterns similar to those in PP, namely predominantly red dots.[11]

Given that PP and other inflammatory skin diseases may sometimes be difficult to differentiate clinically, a more detailed determination of specific dermoscopic patterns of inflammatory skin diseases could be a valuable addition for the clinical assessment.

The aim of this study was to determine the dermoscopic patterns associated with PP, dermatitis, LP and PR and to assess the validity of certain dermoscopic criteria in the diagnosis of PP.


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