Bullous oral erosions: Clues to identifying-and managing-the cause

Certain clues can help you identify the cause of bullous oral lesions. Diffuse oral and labial bullous erosions, sometimes accompanied by target skin lesions, are diagnostic of erythema multiforme. In many conditions, however, the oral lesions themselves are nonspecific, and biopsy (which should be perilesional to include intact epidermis) is required. On light microscopy, the level of epithelial cleavage often suggests the diagnosis, especially for pemphigus vulgaris-a potentially fatal condition. Perhaps more importantly, a portion of the biopsy specimen should be sent for direct immunofluorescence, since many of these conditions are autoimmune and the type and location of the immune complexes present are diagnostic. For example, demonstration of IgG, IgA, and IgM in the intraepithelial layer confirms the diagnosis of pemphigus vulgaris.