History: This lady was diagnosed with coeliac disease about three years ago. She started to develop an itchy skin about two months ago with itchy vesicles on the elbows which she excoriates. She does stick to a gluten free diet. I think this is dermatitis herpetiformis . Histology and immunofluorescence.

Description: dermatitic like rash on the buttocks

Comments: The biopsy shows a superficial and mid dermal perivascular infiltrate of lymphocytes, histiocytes and numerous eosinophils with interstitial eosinophils also present and a mild increase in interstitial cellularity. There are no features to suggest dermatitis herpetiformis. PAS staining is negative. The skin shows no reactivity with IgG, IgA, IgM, C3, C1q and fibrinogen. The features suggest a hypersensitivity reaction to an exogenous antigen such as a bite or a drug.