Dermatitis Herpetiformis and Eczema
What is Dermatitis Herpetiformis
Dermatitis herpetiformis (DH) is celiac disease of the skin. The eruptions are often mistaken for and treated as other skin conditions. The itchy blisters are commonly misdiagnosed as mosquito bites, infected mosquito bites, eczema, contact dermatitis, allergies, heat and/or cold reaction, psoriasis, hives, or unexplained dermatitis. Topical creams and ointments mask the symptoms but do not cure it.
DH is a chronic, permanent condition that only responds to the elimination of gluten. Patients may or may not ever develop gastrointestinal symptoms. Some people suffer from many of the same malabsorption problems as people who have celiac disease. It can be seen in up to 25% of patients with celiac disease, the incidence is greater in men rather than women.
Symptoms of DH
DH is characterized by an intensely itchy, blistering rash. Typically it occurs on extensor surfaces (i.e. elbows, knees) but can occur anywhere on the body including limbs, trunks, groin, hands, fingers, face, scalp, and along the hairline. Often people scratch the itchy skin until it breaks or bleeds.
The blisters tend to recur in the same place each time and are mirrored on both sides of the body. The itching and burning disrupts daily life by interrupting sleep, work and play. Sweat from exercise can make the blisters worse. Unfortunately, scratching further irritates the blisters and can sauce scarring.
What Causes DH?
The ingestion of gluten triggers the immune system to respond with antibodies under the top layer of skin. This causes eruptions of a painfully itchy rash and may progress to red, raised patches of skin (similar to the beginning of a pimple) that develop into small, watery blisters. The itching and burning of the blisters are severe and the urge to scratch them is intense.
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. Only about half of individuals with DH test positive for celiac disease using standard blood screening tests.
Treatment for DH
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 your 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 Gluten-Free Diet
The gluten-free 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 to eliminate gluten for a period of time. For a valid diagnosis, gluten would need to be reintroduced for at least several weeks before testing. Dermatitis herpetiformis is an inherited autoimmune digestive disease and confirmation of DH will help future generations be aware of the risk within the family.
How is DH Different From Eczema?
DH is an autoimmune disorder of the skin, which is associated with celiac disease. It is not typically associated with gluten Intolerance (non-celiac gluten sensitive) patients where as eczema can be associated with both conditions. Like DH, eczema is an inflammatory condition of the skin that can be itchy with red patches but tends to be more of a dry, scaly type rash whereas dermatitis herpetiformis can have more of a blistering like rash. If there is any doubt of the diagnosis a skin biopsy can help differentiate between the two.
Will Eczema Respond to a Gluten-Free Diet?
Yes it is possible. It really depends if one is sensitive to gluten and by going gluten free their eczematous rash improves. Typically there is not just one cause of eczema flare-ups so other causes should also be considered (ie stress, heat, excessive sweating, other food allergies). Usually eczema is associated with other allergic type conditions such as hay fever or asthma.