Psoriasis — SCE Dermatology MCQ

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HardInflammatory DermatosesPsoriasisSCE Dermatology

A 41-year-old woman with psoriatic arthritis has been started on a TNF-alpha inhibitor. Six weeks later, she develops new-onset psoriasiform lesions on her palms and soles that were not present before treatment. What is this phenomenon called?

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Correct answer: E — Paradoxical psoriasis

Paradoxical psoriasis is the new onset or exacerbation of psoriasis (often palmoplantar pustular or plaque type) during treatment with TNF-alpha inhibitors. It occurs in approximately 5% of patients and is thought to be mediated by overproduction of type I interferons by plasmacytoid dendritic cells due to TNF blockade. Management includes topical treatment; if severe, switching to a different class (IL-17 or IL-23 inhibitor) is recommended. This is distinct from treatment failure or Koebner phenomenon.

Reference: BAD 2020 Guidelines for biologic therapy for psoriasis