Pityriasis rosea is a very common, self-limiting exanthematous disorder clinically characterized by oval or round, erythematous patches, often showing a peripheral fine scaling collarette and generally preceded by the onset of a bigger, isolated patch (“herald patch”). Dermatoscopy may enhance the clinical diagnosis of pityriasis rosea by highlighting, both on the herald patch and on the secondary lesions, the characteristic peripheral whitish scaling localized just inside the border of the lesions (“collarette” sign). Not uncommonly, it is possible to detect dotted vessels which, unlike psoriasis, are distributed in an irregular or focal pattern. Diffuse or localized yellowish-orange structureless areas may also be observed in a minority of cases.
KeywordsPityriasis rosea Scaling collarette Herald patch Peripheral whitish scaling Dotted vessels
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