[Pyoderma gangrenosum--clinical, laboratory and therapeutic approaches. Review of 28 cases].

Pyoderma gangrenosum is an uncommon neutrophilic dermatosis, idiopatic in 25-50 percent of cases. We present a retrospective study of 28 patients, admitted to Hospital de São João, EPE, between January of 1990 and June of 2008. Pyoderma gangrenosum was observed more frequently in middle age adults, in the ulcerated form, and predominantly localized in the lower limbs. Pediatric presentation was very rare. In 50 percent of these cases a systemic disease was present and the most frequent was Crohn disease (14% of patients).