Dermatitis herpetiformis (DH) is a chronic, pruritic autoimmune blistering disorder associated with gluten-sensitive enteropathy. DH most commonly affects patients of Northern European descent and occurs more frequently in men than women. While more than 90% of patients have associated gluten-sensitive enteropathy on small bowel biopsy, only 20% exhibit symptoms of intestinal disease at the time of diagnosis. The pathogenesis involves the deposition of IgA immune complexes in the papillary dermis. The associated autoantigen is an epidermal transglutaminase, transglutaminase 3 (TG3). There is a genetic predisposition to the disease, as it is associated with certain human leukocyte antigen (HLA) haplotypes, HLA class II DQ2.

The disease manifests as an intermittent pruritic, papulovesicular eruption over the extensor surfaces of the extremities, buttocks, and scalp. Many patients who adhere to a strict gluten-free diet experience complete remission of their disease.

Patients with DH are at an increased risk of developing thyroid disease, most commonly Hashimoto thyroiditis. Insulin-dependent diabetes mellitus and pernicious anemia have also been reported. Patients with gluten-sensitive enteropathy are also at increased risk of enteropathy-associated T-cell lymphoma and therefore warrant close surveillance. Gluten avoidance may decrease the risk for lymphoma. A population-based study from Finland strongly suggests an increased risk of bullous pemphigoid in patients with DH.