Dermatitis herpetiformis (DH) is a cutaneous symptom of celiac disease that manifests as a severe itch and blistering symmetrical rash on the elbows, knees, and buttocks. Though overt gastrointestinal symptoms are uncommon, three-quarters of DH patients have villous atrophy in the small bowel, with the remainder having celiac-type inflammatory alterations. DH primarily affects adults, with males being affected somewhat more than females. The average age of onset is around 50 years. Granular immunoglobulin A deposits in the papillary dermis corroborate the diagnosis of DH. In firmly bound immune complexes, the DH autoantigen, transglutaminase 3, is deposited at the same location. The current DH-to-celiac disease prevalence ratio is 1:8. The prevalence of DH is decreasing, but celiac disease is growing, most likely due to better diagnoses. In the case of DH, the therapy of choice for all patients is a gluten-free diet (GFD) that includes uncontaminated oats. Most people require extra dapsone at the start to manage the rash and itching.
Dapsone can be discontinued after an average of two years, and a rigorous lifetime GFD is all that is necessary. Dietary adherence provides a favourable long-term prognosis for DH patients, with a normal quality of life and low all-cause mortality.
Reference: https://link.springer.com/article/10.1007/s40257-020-00584-2
