Polymorphic light eruption — SCE Dermatology MCQ
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Correct answer: E — A supervised pre-season course of narrowband UVB phototherapy to induce hardening
Explanation lettering: E = shown as A · D = shown as B · B = shown as C · A = shown as D · C = shown as E
C is correct. In severe recurrent polymorphic light eruption, a supervised course of phototherapy before the sunny season can induce skin hardening and reduce subsequent reactions. Narrowband UVB is commonly used, with dose escalation controlled to minimise provocation and burns. One intense exposure is unsafe and does not reproduce a graded desensitisation course. Doxycycline itself can cause photosensitivity and does not prevent PLE. Photopatch testing diagnoses photoallergic contact dermatitis rather than treating PLE. Photoprotection remains necessary because hardening is not complete or permanent, and systemic immunosuppression is reserved for exceptional refractory disease.
Reference: BAD polymorphic light eruption information: https://www.bad.org.uk/pils/polymorphic-light-eruption