Dermatitis herpetiformis and celiac disease are both primarily associated with the HLA-DQ (alpha 1*0501, beta 1*02) or the HLA-DQ (alpha 1*03, beta 1*0302) heterodimers.

HLA-DRB1,-DQA1, and -DQB1 genomic typing of 50 patients with dermatitis herpetiformis and of 290 healthy blood donors was performed. Genes encoding the DQ (alpha 1*0501, beta 1*02) heterodimer were carried by 43 (86%) of the patients and 72 (25%) of the controls. Of the remaining seven patients six (12% of all the patients) carried genes encoding the DQ (alpha 1*03, beta 1*0302) heterodimer. These HLA associations are very similar to those observed in patients with celiac disease. We thus conclude that dermatitis herpetiformis and celiac disease are associated to the very same HLA-DQ alpha beta heterodimers.