Dermatitis Herpetiformis — SCE Dermatology MCQ

Correct answer: C — Strict gluten-free diet and Dapsone

The correct answer is C, strict gluten-free diet and Dapsone. This patient's presentation, intensely pruritic grouped vesicles on extensor surfaces (elbows, knees, buttocks) in a coeliac patient, with granular IgA deposition at the dermal papillary tips on direct immunofluorescence, is diagnostic of dermatitis herpetiformis (DH), the cutaneous manifestation of gluten-sensitive enteropathy. Dapsone provides rapid suppression of neutrophil-mediated inflammation and controls the itch and blistering within days, but it does not address the underlying gluten-driven immune process. A strict lifelong gluten-free diet treats the enteropathy and, over months, allows the skin disease to remit, permitting dapsone to be tapered and often stopped; this combination is the recommended long-term strategy in UK dermatology guidance. Why the other options are wrong: A. Oral Ciclosporin: Not used in DH; ciclosporin has no established role in this IgA-mediated disease and carries nephrotoxicity risk without evidence of benefit. D. Topical clobetasol propionate alone: Potent topical steroids may give partial symptomatic relief but do not control the systemic gluten-driven process or prevent new lesion formation, and are not disease-modifying. E. Oral Prednisolone: Systemic steroids are generally ineffective in DH and are not recommended as they do not reliably suppress the granular IgA-driven neutrophilic response. B. Rituximab: Not indicated; DH is not a first-line rituximab-responsive disease, unlike some other IgA or autoimmune bullous disorders where B-cell depletion is used. Key point: In dermatitis herpetiformis, dapsone gives fast symptom control while a strict lifelong gluten-free diet is the only long-term disease-modifying treatment, allowing dapsone withdrawal over time.

Reference: British Association of Dermatologists guidelines for the management of dermatitis herpetiformis 2018 (Harman KE et al., Br J Dermatol); BAD patient information leaflet, Dermatitis herpetiformis (gluten sensitivity), www.bad.org.uk/pils/dermatitis-herpetiformis-gluten-sensitivity