6th July 2023

Dermatitis Herpetiformis

A rare chronic autoimmune blistering skin condition that is associated with coeliac disease (a gluten-sensitive enteropathy) in 90% of patients. More common in men and typically presents between 15-40 years old. Loss of immune tolerance to gluten peptides triggers the production of IgA antibodies and an autoimmune process targeting both the skin and intestinal submucosa.

Classically presents as intensely itchy clusters of vesicles on erythematous or normal-looking skin. Vesicles are often broken through scratching leaving erosions. Distribution is symmetrical and commonly affects the extensors, including the elbows, knees, buttocks and scalp. Symptoms of gastrointestinal disturbance and malabsorption may also be present.

Dermatitis herpetiformis on the abdomen

Image Source: Wikimedia Commons (2010). Dermatitis-herpetiformis, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Dermatitis-herpetiformis.jpg (Accessed on: 10 March 2022).

Skin biopsy demonstrates IgA deposits at the dermal papillae and subepidermal blisters on direct immunofluorescence. Coeliac disease should also be tested for. A lifelong gluten-free diet is strongly recommended in these patients. Dapsone is the first choice in cases that cannot be managed with dietary changes alone and will control eruptions and itch. However, regular blood monitoring is required due to the risk of haemolytic anaemia and agranulocytosis.