Prepared by: CCA Professional Advisory Council, June 2016
Definition: Dermatitis herpetiformis (DH) is “celiac disease of the skin”. It is a chronic skin condition with a characteristic rash with intense itching and burning sensations.
Causes: Genetic factors, the immune system, and a sensitivity to gluten play a role in this disorder. The precise mechanisms remain unknown.
Incidence: The prevalence of DH is about 10 cases per 100,000 population. It is more common in males. Onset is most frequently in the second to fourth decade of life. It is rare in children. About 10-15% of patients with celiac disease have DH. A new unscratched lesion is red, raised, and usually small, with a tiny blister in the centre. However, if scratched, crusting appears on the surface. The burning or stinging sensation can be very intense. The most common areas are the elbows, knees, back of the neck, scalp, upper back, and the buttocks. Facial and hair-line lesions are not uncommon. The inside of the mouth is rarely affected. The rash has a symmetric distribution.
Diagnosis: DH can be diagnosed with a biopsy taken from uninvolved skin adjacent to blisters or erosions. The vast majority of patients will also have features of celiac disease (villous atrophy) and do not require a small intestinal biopsy to confirm the diagnosis. The skin symptoms usually predominate over intestinal symptoms. Serological tests for celiac disease may be negative. Like celiac disease, patients may have nutritional deficiencies. Laboratory tests should be performed including complete blood count, iron studies, albumin, alkaline phosphatase, folate, phosphate, calcium and vitamin D, as appropriate for each patient.
Management: Treatment of DH consists of medications and a gluten-free diet. Oral dapsone (Avlosulfon) is often used to treat the skin rash. The response is often dramatic with rapid relief of burning and improvement in the rash. A strict gluten-free diet should be consumed with an elimination of all foods and beverages containing wheat, rye or barley. A referral to a dietitian with expertise in the gluten-free diet is recommended. Since DH is a chronic disorder, regular follow-up with the physician and dietitian is important.