Immunologic studies of lesional and nonlesional “normal”-appearing skin of a 32-year-old man with epidermolysis bullosa acquisita (EBA) revealed the following: (1) Noninflammatory subepidermal bullae formation in the periodic acid-Schiff (PAS)-positive basement membrane; (2) linear deposits of polyclonal IgG, Clq, C4, C3, properdin, and factor B at the dermoepidermal junction; IgA and IgM were not found; (3) broad subbasal lamina electron-dense amorphous material (EDAM) lacking amyloid features by electron microscopy; EDAM was not associated with anchoring fibers; (4) cleavage plane below the EDAM. Gastrointestinal endoscopy showed inflammatory erosions in the duodenum. Microscopy of the involved duodenum showed a mixed inflammatory infiltrate, subepithelial edema, microvesiculation, and granular deposits of IgG and C3, but no EDAM. However, EDAM and immune reactants were found in the esophagus. EBA is a distinct entity characterized by the presence and location of EDAM ultrastructurally, and it may represent a gastrointestinal-cutaneous syndrome with an immune pathogenesis.