Granular IgA Deposits in the Skin of Patients with Coeliac Disease: Is it Always Dermatitis Herpetiformis?

Coeliac disease is an immune-mediated enteropathy driven by gluten, which can be associated with dermatitis herpetiformis. The presence of granular IgA deposits, detected by direct immunofluorescence, is the hallmark of dermatitis herpetiformis; nevertheless, IgA deposits have also been demonstrated in healthy skin of patients with coeliac disease. The main objective of this study was to investigate whether IgA deposits could be found in the skin of patients with coeliac disease who have non-dermatitis herpetiformis inflammatory skin diseases. Direct immunofluorescence was performed on perilesional skin biopsies of 6 patients with coeliac disease with non-dermatitis herpetiformis inflammatory skin diseases and, as control, on 12 non-coeliac patients with inflammatory skin diseases. IgA deposits were found in all of the patients with coeliac disease, but were absent in the control group. In conclusion, IgA deposits may be considered an immunopathological marker for coeliac disease; therefore, patients with coeliac disease showing skin manifestations with positive direct immunofluorescence should be investigated carefully in order to make a differential diagnosis between dermatitis herpetiformis and other non-dermatitis herpetiformis inflammatory skin diseases.