In addition to recognizing the clinical findings, a diagnosis of DH can be made by performing a specific type of skin biopsy called a punch biopsy. This involves injecting a local anesthetic and using a small, cookie-cutter-like punch to remove a small sample of the skin adjacent to where the lesions are. The incision is then closed with one stitch. The skin sample is analyzed using direct fluorescence microscopy. Skin biopsies of people with DH are positive for immunoglobulin A (IgA) deposits which will appear in a granular pattern.
Blood tests for antibodies that are commonly found in people with CD, such as anti-tissue glutaminase also supplement the diagnosis of DH. If blood antibody tests are positive and the skin punch biopsy has the typical findings of DH, patients do not need an intestinal biopsy to confirm the diagnosis of celiac disease.
Following a strict life-long gluten-free diet is important for controlling DH. The gluten-free diet can be complex so patients should be referred to a registered dietitian with expertise in CD for a nutrition assessment, education, and follow-up. However, it can take one to two years even with a strictly gluten-free diet for the skin rash to totally resolve.
A family of antibiotics known as sulfones can also be prescribed to reduce the swelling and the discomfort caused by the rash. Dapsone is a common antibacterial within this family used to treat DH. Patients typically feel relief within 48 to 72 hours of taking this medication. This medication may be used along with other medications for at least 4-6 months. In some cases, it may be taken for longer. However, this medication does not replace the importance of maintaining a strict gluten-free diet.