Dermatitis herpetiformis is an intensely itchy blistering skin condition linked to gluten sensitivity and coeliac disease. It is not caused by the herpes virus. The name refers to the clustered appearance of the blisters.
The condition is a skin manifestation of gluten-driven autoimmunity. It can occur with or without obvious bowel symptoms, so people may not realise that their rash is linked to gluten.
Symptoms
Dermatitis herpetiformis usually causes very itchy bumps and small blisters. They often appear symmetrically on the elbows, knees, buttocks, scalp, shoulders or back. Scratching can break the blisters, leaving crusts, marks or excoriations.
The rash may come and go. Burning, stinging or intense itching can happen before visible lesions appear.
Some people also have symptoms of coeliac disease, such as bloating, diarrhoea, abdominal pain, tiredness, anaemia or weight change, but many have few digestive symptoms.
Cause
The condition is triggered by gluten in people with genetic susceptibility. Gluten exposure can lead to IgA antibody deposits in the skin, which then drive inflammation and blistering.
Dermatitis herpetiformis and coeliac disease are closely related. A person with dermatitis herpetiformis is usually treated as having gluten-sensitive disease even if bowel symptoms are mild.
Diagnosis
Diagnosis is usually confirmed by a skin biopsy taken from normal-looking skin close to a blister. Direct immunofluorescence can show IgA deposits in a pattern typical of dermatitis herpetiformis.
Blood tests for coeliac-related antibodies may also be used. Testing works best before a gluten-free diet has already been started, so people should speak to a clinician before removing gluten if dermatitis herpetiformis or coeliac disease is suspected.
Treatment
The long-term treatment is a strict lifelong gluten-free diet. This reduces rash activity, helps the gut, and can reduce the need for medicine over time. Skin improvement can be slow, and it may take many months for the diet to have its full effect.
Dapsone can reduce itch and blistering quickly, but it does not treat the underlying gluten sensitivity. People taking dapsone need medical monitoring because it can affect the blood and liver. Sulfapyridine or other medicines may be used where dapsone is not suitable.
Topical treatments may help with itch or inflammation, but they do not replace gluten avoidance.
Living With the Condition
Dietetic support is important because gluten-free living affects food choice, nutrition, cost, social eating and label reading. People may also need assessment for complications linked with coeliac disease, including nutritional deficiency and bone health problems.
Accidental gluten exposure can trigger flares. The condition is chronic, but many people gain good control with a strict gluten-free diet and specialist follow-up.
See Also
References
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