A chronic disease of the skin characterised by severe itching, extensive eruption of vesicles (blisters) and papules whichoccur in groups. Patients have HLA antigens -83. -DR3. and -DQ2. In some cases this condition may be associated withgluten-sensitive enteropathy. Patients with dermatitis herpetiformis are at increased risk for gastrointestinal lymphoma, anthis risk is reduced by a gluten-free diet.

Diagnosis is made by light microscopy, which demonstrates neutrophils at the dermal papillary tips. Directimmunofluorescence studies show granular deposits of IgA along the dermal papillae. Circulating antiendomysiumantibodies and antibodies to tissue transglutaminase are present in 70% of cases. Differential diagnosis includes weepingor encrusted lesions (crusted lesions), impetigo, contact dermatitis (acute).

Strict long-term avoidance of dietary gluten has been shown to decrease the dose of dapsone (usually 100-200 mg/day)required to control the disease and may even eliminate the need for drug treatment.