In this autoimmune disorder, glutens in wheat, rye, and barley products cause the immune system to attack the skin.
People have red, itchy blisters and hivelike swellings on various areas of the body.
Doctors diagnose dermatitis herpetiformis by examining skin samples under a microscope.
People usually respond to treatment with dapsone or sulfapyridine and a gluten-free diet.
(See also Overview of Blistering Disorders.)
Dermatitis herpetiformis often occurs in young adults but can occur in children and older people. It is rare in blacks and Asians.
Despite its name, dermatitis herpetiformis has nothing to do with the herpesvirus. The term herpetiformis is used to describe the way in which the blisters cluster together (similar to a rash caused by some herpesviruses).
In people with dermatitis herpetiformis, glutens (proteins) in wheat, rye, and barley products somehow activate the immune system, which attacks parts of the skin and causes the rash and itching. People with dermatitis herpetiformis often have celiac disease, which is an intestinal disorder caused by sensitivity to gluten, but they may not have symptoms resulting from the celiac disease. People also have a higher incidence of other autoimmune diseases, such as thyroiditis, systemic lupus erythematosus, sarcoidosis, pernicious anemia, and diabetes. People with dermatitis herpetiformis occasionally develop lymphoma in the intestines.
The blisters and hives usually develop gradually, mostly on the elbows, knees, buttocks, lower back, and back of the head, but can develop suddenly. Sometimes blisters break out on the face and neck. Because itching is intense and the skin is fragile, blisters usually break quickly, and few remain intact for the doctor to see. Blisters may develop in the mouth but they usually do not cause symptoms. Itching and burning are likely to be severe.
Iodides and iodine-containing preparations (such as kelp and seaweed products and certain skin cleansers) may worsen the rash. Some specialists also suggest avoiding iodized salt.
The blisters do not go away without treatment. People are usually placed on a gluten-free diet (a diet that is free of wheat, rye, and barley), which is the main treatment for celiac disease.
The drug dapsone, taken by mouth, almost always provides relief in 1 to 3 days but requires that blood counts be checked regularly because dapsone can cause anemia. Sulfapyridine (or, alternatively, sulfasalazine) is also taken by mouth and may be given to people who cannot tolerate dapsone. However, sulfapyridine can cause anemia and low numbers of white blood cells (increasing the risk of infection) and also requires that blood counts be checked regularly.
Once the disease has been brought under control with drugs and people have followed a strict gluten-free diet, drug treatment can sometimes be discontinued. However, some people can never stop taking the drugs. In most people, any re-exposure to gluten, however small, triggers another outbreak. A gluten-free diet that is strictly followed for 5 to 10 years decreases the risk of intestinal lymphoma.