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PLEVA — SCE Dermatology MCQ

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HardInflammatory DermatosesPLEVASCE Dermatology

A young adult has recurrent crops of erythematous papules that vesiculate, crust and leave varioliform scars. Histology shows parakeratosis, interface injury, erythrocyte extravasation and a wedge-shaped lymphocytic infiltrate. Which diagnosis best fits?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: E — PLEVA with necrotic keratinocytes and interface dermatitis

Explanation lettering: D = shown as C · E = shown as D · C = shown as E

C is correct. Crops at different stages, evolution through necrosis or crusting and varioliform scarring, together with interface change and a wedge-shaped lymphocytic infiltrate, support PLEVA. Lymphomatoid papulosis can be clinically similar and requires exclusion when atypical CD30-positive cells dominate. Guttate psoriasis lacks necrotic evolution and interface injury; pityriasis rosea does not usually ulcerate or scar; and secondary syphilis has a different systemic and histological context. Clinicopathological correlation matters because PLEVA exists on a spectrum with pityriasis lichenoides chronica and can rarely present as febrile ulceronecrotic disease.

Reference: DermNet PLEVA: https://dermnetnz.org/topics/pityriasis-lichenoides