Dermatitis Herpetiformis

Key Features

• Highest prevalence in northern Europe

• Is associated with HLA antigens -B8, -DR3, and -DQ2

• Patients may have gluten-sensitive enteropathy; among patients with celiac disease, about 1 in 8 develop dermatitis herpetiformis

• Three-fourths of patients have villous atrophy on small bowel biopsy; however, GI symptoms are subclinical in most

• Ingestion of gluten plays a role in the exacerbation of skin lesions

Clinical Findings

• Uncommon disease manifested by pruritic papules, vesicles, and papulovesicles mainly on the elbows, knees, buttocks, posterior neck, scalp

• Patients with dermatitis herpetiformis are at increased risk for gastrointestinal lymphoma, and this risk is reduced by a gluten-free diet

Diagnosis

• Diagnosis is made by light microscopy, which demonstrates neutrophils at the dermal papillary tips

• Direct immunofluorescence studies show granular deposits of IgA along the dermal papillae

• Circulating antibodies to tissue transglutaminase are present in 90% of cases

• Nonsteroidal anti-inflammatory drugs may cause flares

• Differential diagnosis

  • Weeping or encrusted lesions (crusted lesions)

  • Impetigo

  • Contact dermatitis (acute)

• Any vesicular dermatitis can become crusted

Treatment

• Strict long-term avoidance of dietary gluten may

  • Eliminate the need for treatment

  • Decrease the dose of dapsone (usually 100–200 mg orally daily) required to control the disease