Dermatitis Herpetiformis
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Published July 28, 2021
What you need to know about dermatitis herpetiformis
Dermatitis Herpetiformis (DH) is a form of celiac disease. It is a skin condition characterized by groups of itchy blisters. The ingestion of gluten (a protein contained in wheat, rye and barley) triggers an immune system response that deposits lgA antibodies under the top layer of skin. IgA antibodies are present in affected as well as unaffected skin. If you have DH and do not follow a gluten-free diet, you may develop the intestinal damage which is characteristic of celiac disease. In DH, the primary lesion is on the skin rather than the small intestine. The degree of damage to the small intestine is often less severe or more patchy than in those with celiac disease who do not have DH. DH is more common in men than in women, affects approximately 10-15% of people with celiac disease, and is typically diagnosed in adulthood. DH is permanent and symptoms/damage will occur if gluten is consumed.
Symptoms
The lgA deposits result in eruptions of a painfully itchy rash and may progress to red, raised patches of skin that develop into small, watery blisters. The itching and burning of the eruptions are severe and the urge to scratch them is intense. Scratching will further irritate the eruptions. Eruptions commonly occur on pressure points – around the elbows, the front of the knees, the buttocks, back, shoulders, face, and scalp, but can occur anywhere. Eruptions are usually bilateral, occurring on both sides of the body. Obvious gastrointestinal symptoms in DH are uncommon.
Diagnosis
If the eruptions appear to be DH, your dermatologist will take a small biopsy of unaffected skin, next to an eruption. The presence of IgA deposits confirms a diagnosis of DH. An endoscopy is not necessary for diagnosing DH. Only about half of individuals with DH test positive for celiac disease using standard CD blood screening tests. Dermatitis herpetiformis is an inherited autoimmune digestive disease and confirmation of DH will help future generations be aware of the risk within the family.
Treatment
Strictly following a gluten-free diet for life is the only complete treatment. This involves the elimination of wheat, rye, barley, and foods made from these grains (or their derivatives) from the diet. It may take two or more years for the lgA deposits under the skin to completely clear. A medication called Dapsone may also be prescribed. You will need to follow up with your doctor on a regular basis if you use this drug. Dapsone allows the eruptions to heal, but does not cure DH. Discuss the potential side effects of this drug with your doctor before starting it. Your goal should be to take as little as possible for as short a time as required to allow the diet to control the DH.
The Diet
The gluten-free (GF) diet is a lifelong commitment and should not be started before being properly diagnosed with DH. Starting the diet without complete testing is not recommended and makes later diagnosis difficult. Tests to confirm DH could be negative if a person were on a GF diet for a period of time. For a valid diagnosis, gluten would need to be reintroduced for at least several weeks before testing.
Prognosis
Excellent, if you stay on the gluten-free diet. The severity and frequency of eruptions will decrease as you continue with the diet. Iodine and sun may trigger eruptions in some people. However, iodine is an essential nutrient and should not be removed from the diet without a physician’s supervision.