Beloff and Peters,1 in a study of thermal burns, first suggested the possibility that bullous formation may be mediated by proteolytic enzymes. Stoughton2 produced enzymatic cytolysis in formalin-fixed epidermis with a factor obtained from fecal filtrates of patients with ulcerative colitis; acantholysis, separation of epithelial cells, and subsequent blister formation were observed. The histologic findings were "very similar to those of pemphigus vulgaris." In a later study, Stoughton and Novak3 reported that mild heat damage resulted in enzymatic disruption of tonofibrils and intercellular bridges in human epidermis.
Cliffton4 has reported increased antiproteolytic activity in the serum of patients with extensive carcinomatosis. In this connection, pemphigus-like eruptions have been observed in patients with thoracic or abdominal carcinoma.
Consideration of the above findings suggests that pemphigus bullae may be produced by action of proteolytic enzymes on epidermis; this possibility