Two Caucasian sisters, XZ and YZ, suffered from DH. However, the clinical course of their diseases was different; patient XZ, contrary to her sister YZ, suffered besides dermatitis herpetiformis (DH) also from coeliac disease (CD) and an autoimmune thyroid disease. The sisters were ordered to adhere to gluten-free diet and dapsone was prescribed, however, patient XZ developed a hypersensitivity to dapsone. The HLA typing disclosed that they were homozygous and that they shared HLA alleles DQB1*0201. Our results confirm the known association of DH to other autoimmune disorders and its well established association the HLA-DQB1*0201 allele. Although DH is generally not regarded as a familial disease our case report suggests its familial character (Fig. 3, Ref. 10). Full Text (Free, PDF) www.bmj.sk.