Etiology

• Most likely genetic predisposition to autoimmune reaction (associated with HLA-DR3 and HLA-DQ2)
• Associated with celiac disease and sensitivity to potassium iodide (e.g., contrast medium)

Clinical features

• Tense, grouped subepidermal vesicles, papules, and/or bullae (herpetiform appearance)
• Intense pruritus
• Bilateral, symmetrical distribution, commonly over elbows, knees, buttocks, shoulders, scalp
• No mucosal involvement

Diagnostics

• IgA autoantibodies against tissue transglutaminase
• Histology and immunohistochemistry
  • Subepidermal vesicle formation
  • Neutrophilic papillary microabscesses
  • Deposition of granular IgA in dermal papillae