Direct immunofluorescence in pyoderma gangrenosum

Direct immunofluorescence was done in fifty-one cases of pyoderma gangrenosum. Biopsy specimens were taken from the peripheral erythematous zone of the lesion. In thirty-one cases (61%), there was positive immunofluorescence, with perivascular deposition of immune reactants being the most frequent pattern (twenty-seven cases). These findings support a vasculitic pathogenesis of pyoderma gangrenosum.