A patient with dermatitis herpetiformis adheres strictly to a gluten-free diet. Why does the rash nevertheless take many months to improve even though intestinal villous atrophy recovers faster?

• A Keratinocytes continue producing IgA independently of dietary gluten
• B Epidermal transglutaminase-IgA complexes deposited in papillary dermis clear very slowly ✓
• C Gluten-free diets increase circulating dapsone levels, causing drug resistance
• D Recovery of intestinal permeability paradoxically increases immune complex formation

Explanation

In dermatitis herpetiformis, IgA directed against epidermal transglutaminase deposits as granular complexes in dermal papillae. These preformed cutaneous deposits are cleared slowly, so skin lesions lag behind mucosal healing by roughly 6 months to 2 years despite strict dietary adherence. Dapsone suppresses the eruption within days but has no effect on the enteropathy, which is exactly why the two treatments act on different time scales.

Reference: Fitzpatrick's Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.