Recurrent Erythema Multiforme — SCE Dermatology MCQ

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ModerateDrug ReactionsRecurrent Erythema MultiformeSCE Dermatology

A 42-year-old woman has recurrent erythema multiforme (EM) with typical target lesions on her hands and feet. She has 5-6 episodes per year, each preceded by herpes labialis. What prophylactic treatment is recommended?

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Correct answer: A — Continuous oral Aciclovir or Valaciclovir prophylaxis

For recurrent EM triggered by HSV (the commonest cause of recurrent EM, responsible for >90% of cases), continuous antiviral prophylaxis with oral Aciclovir 400 mg BD or Valaciclovir 500 mg-1 g daily is recommended. This prevents HSV reactivation, thereby preventing EM episodes. Prophylaxis is typically continued for 6-12 months then reassessed. If EM recurs after stopping prophylaxis, longer-term or indefinite treatment may be needed. This approach is highly effective, reducing recurrence rates by >80%. For the rare cases of recurrent EM not associated with HSV, Dapsone or Azathioprine may be considered.

Reference: BAD 2019; BJD Erythema Multiforme; NICE