Dermatitis herpetiformis is an autoimmune disease triggered by eating gluten. Most commonly seen in people with celiac disease, it causes an itchy, blistering, burning rash. It can affect people of any age, but typically first occurs in people in their 30s, is more common in males than females, and is rare in children.
Regardless of who has it or how old they are, the best treatment for people with dermatitis herpetiformis is to remove gluten from their diet.
What is dermatitis herpetiformis?
Dermatitis herpetiformis, also known as Duhring disease, is a rare autoimmune disease of the skin. It is characterized by an extremely itchy, inflamed, blistering rash that most commonly develops on the elbows, knees, buttocks, back, and scalp. The rash develops after gluten is consumed. Most people who have dermatitis herpetiformis also have celiac disease, an autoimmune disease that primarily affects the small intestine and—like dermatitis herpetiformis—is triggered by the consumption of gluten.
What causes dermatitis herpetiformis?
The skin rash associated with dermatitis herpetiformis is caused by an abnormal immune response to gluten. In a susceptible person, the process begins when gluten-containing food is eaten. The gluten triggers an immune response in which a self-reactive antibody of the immunoglobulin A (IgA) type moves to and deposits in the skin. Once there, the antibody prompts an inflammatory response that ultimately leads to the eruption of an inflamed, itchy, blistering skin rash.
Genetic factors play an important role in dermatitis herpetiformis. Around 10 to 15% of people with a parent or sibling who has celiac disease or dermatitis herpetiformis. Researchers have identified certain genes that predispose people to dermatitis herpetiformis. In addition to gluten-containing foods, certain chemicals and medications can also bring on symptoms in people with this condition. For instance, iodine, a chemical added to many foods, and nonsteroidal anti-inflammatory medications (NSAIDs) like aspirin, ibuprofen, and naproxen may spark flare-ups.
What are the symptoms of dermatitis herpetiformis?
Dermatitis herpetiformis may cause skin, oral, and gastrointestinal symptoms.
- Groups of extremely itchy blisters; a burning sensation may develop
- Commonly affected areas are the elbows, forearms, knees, buttocks, back, and/or scalp, although the face and groin may sometimes be affected
- The skin rash tends to develop equally on the left and right sides of the body
- Blisters in the mouth
- Tooth enamel defects (discoloration, pitting, or banding)
- Stomach pain
Though most people with dermatitis herpetiformis also have celiac disease, only about 20% of them also experience gastrointestinal symptoms.
In addition to these symptoms, people who have dermatitis herpetiformis may be at increased risk for small-bowel lymphoma and some other autoimmune diseases including autoimmune thyroid disease (Hashimoto thyroiditis), pernicious anemia, and diabetes.
How is dermatitis herpetiformis diagnosed?
The first step in making a diagnosis involves asking questions about your symptoms and when they started. Your doctor may also ask if your family—especially any first-degree relatives—has a history of celiac disease.
Your skin will be closely examined as well. Because the blistering rash of dermatitis herpetiformis can resemble rashes caused by other skin conditions, making a diagnosis based on how the skin looks is difficult. Additional tests are needed to confirm the diagnosis.
One of these additional tests is a skin biopsy. Usually, this is done with what’s called a punch biopsy, a procedure during which a tiny, cylindrical piece of skin is removed using a specialized tool. A tissue sample is taken from skin that is next to but unaffected by the rash. A pathologist will then examine the skin sample under a microscope to check for the presence of autoreactive IgA antibodies, which are produced by the immune system when gluten-sensitive people ingest gluten.
These auto-reactive IgA antibodies are nearly always present in the skin biopsies of people with dermatitis herpetiformis. Your doctor will also order blood tests to confirm the diagnosis and determine if you have celiac disease. If your doctor suspects you have celiac disease, he or she may order a biopsy of the small intestine.
How is dermatitis herpetiformis treated?
The first thing to do if you’ve been diagnosed with dermatitis herpetiformis is avoid gluten. Most people with the condition also benefit from medication.
- Gluten avoidance. Anyone who has dermatitis herpetiformis should avoid foods and beverages that contain gluten. Removing gluten from the diet will help symptoms recede quickly, though it may take several months or up to a year or longer for all symptoms to disappear. Lifelong adherence to a strict gluten-free is necessary, as any ingestion of gluten can trigger flare-ups.
- Topical corticosteroids. These inflammation-reducing lotions, creams, and ointments can help relieve itchy skin.
- Dapsone. Usually used as a first-line therapy for the treatment of dermatitis herpetiformis, dapsone reduces itching and rash within one to three days. People may need to take this medication for years, but those who stick to a gluten-free diet may be able to get by with lower doses or even stop taking the medication entirely. Because dapsone can cause harmful side effects, including anemia, anyone taking this medication must have regular blood work to monitor for possible development of anemia and other adverse effects.
- Sulfasalazine and sulfapyradine. People whose symptoms do not improve with dapsone or who cannot tolerate it may be prescribed sulfapyradine or sulfasalazine. These drugs can reduce the skin inflammation that occurs in dermatitis herpetiformis.