Clinical Features:
(1) usually occurs in young and middle-aged adults, but may also occur in children and the elderly
(2) papules, vesicles, bullae, and crusts on an erythematous base
(3) often symmetrical on extensor surfaces; elbows, shoulders, knees, sacrum, buttocks, scalp, posterior nuchal; rare on mucous membranes, palms and soles
(4) Patients often complain of burning and/or intensely pruritus, but rare patients may be relatively asymptomatic.
(5) Prompt response to dapsone, sulfoxone or sulfapyridine, with exacerbation on stopping therapy.
(6) Exacerbation of lesions on exposure to nonsteroidal anti-inflammatory drugs (NSAIDS).
Histologic Features:
(1) neutrophilic microabscesses at the tips of dermal papillae in erythematous nonbullous areas, often with eosinophils
(2) progression to subepidermal bullae
(3) granular (nonlinear) deposits of IgA and often C3 at the tips of the dermal papillae. Some patients may have a negative initial test for IgA, but are often positive on repeat testing; the absence of IgA on 2 or more occasions is evidence against the diagnosis.
Gastrointestinal disease:
(1) Patients may have a gluten-sensitive enteropathy with malabsorption.
(2) The small biopsy is often normal.
(3) Many patients clinically respond to a gluten-free diet, with improvement of the skin lesions.
Laboratory Findings:
(1) HLA types: HLA-B8, HLA-DR3, HLA-DQw2 common. Almost all patients have genes that encode HLA-DQ (alpha 1*0501, beta 1*02) or (alpha 1*03, beta 1*0302), a finding identical to that seen in patients with celiac disease.
(2) serum anti-endomysial and/or antigliadin antibodies are often present
