Psoriasis — SCE Dermatology MCQ

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EasyInflammatory DermatosesPsoriasisSCE Dermatology

A 40-year-old man with psoriasis develops palmoplantar keratoderma with fissuring that significantly impairs his daily activities. What topical keratolytic agent is most appropriate to reduce the thick scale before applying active treatment?

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Correct answer: D — Salicylic acid 5-10% in white soft paraffin or urea 10-40% cream

For thick hyperkeratotic psoriasis of the palms and soles, keratolytic agents (Salicylic acid 5-10% or Urea 10-40%) are used as descaling agents to reduce the thick stratum corneum before applying active topical treatments (corticosteroids, Calcipotriol). Without prior descaling, active treatments cannot penetrate the thick scale effectively. Salicylic acid and high-concentration urea soften keratin through chemical disruption of corneocyte cohesion. They should be applied under occlusion (cling film, cotton gloves/socks) overnight for best effect. Once scale is reduced, potent topical corticosteroids, Calcipotriol/Betamethasone, or hand/foot PUVA can be applied more effectively.

Reference: BAD 2020 Psoriasis Guidelines; NICE CG153