Dermatitis Herpitiforms

Dermatitis herpetiformis (DH) is a rare but persistent immunobullous disease that has been linked to coeliac disease

• DH predominantly affects Caucasians aged 15–40 years, but may occur in those younger or older and in other races.
• There is a 2:1 male-to-female ratio.
• More females under the age of 20 are affected than males.
• There is a genetic predisposition and association with human leukocyte antigens (HLAs) DQ2 and DQ8.
• Some patients have a personal or family history of other autoimmune disorders such as viteligo, type 1 DM, alopasia
• DH and coeliac disease are due to intolerance to the gliadin fraction of gluten found in wheat, rye and barley.
• Gluten triggers production of IgA antibodies and an autoimmune process that targets the skin and gut.
• In coeliac disease, gluten causes intestinal inflammation resulting in diarrhoea, tiredness, weight loss and abdominal discomfort.

What are the clinical features of dermatitis herpetiformis?

• DH has a symmetrical distribution.
• Lesions most commonly appear on scalp, shoulders, buttocks, elbows and knees.
• It is characterised extremely itchy papules and vesicles on normal or reddened skin.
• They often appear in groups or serpiginous clusters.
• Blisters are often eroded and crusted due to immediate scratching.
• DH may also present initially as digital petechiae.
• Flat red patches, thickened plaques and wheals may occur resembling other inflammatory skin conditions such as dermatitis, scabies and papular urticaria. 
• Lesions resolve to leave postinflammatory hypopigmentation and hyperpigmentation.