Dermatitis Herpetiformis

Definition

Dermatitis herpetiformis (DH) is a chronic skin condition with a characteristic pattern of lesions, 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 details remain unknown.

Incidence

DH is not uncommon. It affects males and females equally and occurs in about 1:100,000 people. It is more common in Caucasians than Blacks, and rare in the Japanese population. Onset is most frequently in the late second to the fourth decades of life.

Characteristics

A new unscratched lesion is red, raised, and usually less than 1 cm in diameter with a tiny blister at the centre. However, if scratched, crusting appears on the surface. The ‘burning” or “stinging” sensation is different from a “regular” itch, and can often occur 8-12 hours before a lesion appears.

Areas Affected

The most common areas are the elbows, knees, back of the neck, scalp, the upper back, and the buttocks. Facial and hair-line lesions are not uncommon; the inside of the mouth is rarely affected. The rash has symmetric distribution.

Diagnosis

DH is associated with an abnormal mucosal lining of the small intestine in most individuals, identical to those changes seen in persons who have celiac disease. Most people with DH have little or no bowel complaints while only a small percentage may have diarrhea, bloating, bulky stools or abdominal cramps. Despite the possible lack of bowel complaints, diagnosis of DH requires a small bowel biopsy, performed by a gastroenterologist.

Management

Treatment is by drugs, and diet restrictions.

Drugs: Dapsone (Avlosulfon) or related sulphones: The response is dramatic. Within 24-48 hours the burning is relieved and the rash starts to disappear. The aim is to use the smallest dose possible to keep the itch and rash under control. It has no effect on the gut abnormality.

Diet: Gluten-free Diet: Elimination of all wheat, rye, barley, oats, triticale, and any parts thereof from the diet will result in:

  • the skin lesions improving
  • the gut returning to normal
  • a substantial reduction in or the elimination of the need for sulphones to control the skin rash
  • a decreased risk of malignancy