Bullous colon lesions in a patient with bullous pemphigoid.

Bullous pemphigoid (BP) is a subepidermal blistering disease associated with circulating autoantibodies directed against structural components of hemidesmosomes, adhesion complexes promoting epithelial-stromal adhesion in human skin, and other complex epithelia. Two hemidesmosomal proteins, the BP antigen 180 (BP180) and the BP antigen 230 (BP230), have been shown to be the target antigens.1,2 BP230 is a cytoplasmic component of the hemidesmosomal plaque, whereas BP180 is a transmembrane protein with a collagenous extracellular domain. These 2 target antigens are expressed, as assessed by immunofluorescence microscopy by using either specific antisera and/or polyclonal BP patient sera, in stratified and some complex epithelia that ultrastructurally exhibit hemidesmosomes at the epithelial-stromal interface: in the skin; the ocular, buccal, and genital mucosa; the esophagus; and trachea.3 These peculiar tissue distributions of BP230 and BP180 explain the potential in patients with BP for involvement of various mucous membranes and the upper GI tract in addition to the skin.4 BP and linear immunoglobulin (Ig) A bullous dermatosis, a condition that might overlap with BP, have been associated with GI disorders such as ulcerative colitis.5-9 However, the exact pathophysiologic relationship remains unclear because small intestine and colon mucosa do not possess bona fide hemidesmosomes with BP180 and BP230 components. This is a description of a patient with typical clinical and immunopathologic features of BP who developed severe bullous lesions of the colon reminiscent of BP, and a discussion of the potential pathogenic link between the immune-mediated subepidermal disorder and the bowel disease. CASE REPORT