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

• The majority (> 90%) of patients with dermatitis herpetiformis also have coeliac disease. Gastrointestinal symptoms may be mild to severe; some patients remain symptom-free.
• Around 15–25% of coeliac patients have concurrent dermatitis herpetiformis. These patients tend to have a more severe intestinal pathology in comparison to those without dermatitis herpetiformis.

PC

• DH has a symmetrical distribution

• lesions appear on the scalp, shoulders, buttocks, elbows, knees

• Prurigo (extremely itchy papules) and vesicles

• Blisters are often eroded and crusted due to immediate scratching

Investigations

Labs:

• Same as for coeliac
• IgA epidermal tranglutaminase antibodies (not present in coeliac)

Skin biopsy - Usually needed to confirm diagnosis:

• Subepidermal blisters
• Neutrophil and easinophil inflammatory cells in dermal papillae
• Granular IgA deposits in dermal papillae