The gangrenous pyoderma is a disease of unknown etiology, with various clinical manifestations, especially cutaneous ones, of difficult diagnosis, chronic evolution and frequent exacerbations and remissions. There is not an effective elective treatment, so the answer to therapy is very variable. We presented the case of a female patient, mestiza, aged 64 years, with personal pathological antecedents of gastritis, arterial hypertension and ischemic cardiopathy, showing a year of evolution ulcerous lesion on the first joint of the right foot with therapeutic failures before the diagnosis. We ordered hematologic and histopathologic studies confirming a gangrenous pyoderma that favorably answered to the therapy with prednisone, dapsone and hyperbaric oxygenation.