Pyoderma gangrenosum

Abstract

Pyoderma gangrenosum (PG) is a rare, chronic, neutrophilic skin disease of unknown origin, characterized by painful, sterile, necrotic ulcers with violaceous undermined borders. It belongs to the group of neutrophilic dermatoses, and it has been characterized as a cutaneous autoinflammatory disease. PG is idiopathic in 40-50 % of patients; however, in the remaining cases, it may be associated with underlying diseases including ulcerative colitis, Crohn’s disease, leukaemia, monoclonal gammopathy, rheumatoid arthritis or immunodeficiencies. PG has been reported as part of PAPA, PASH and PAPASH syndromes. Four clinical variants of PG have been described: classic (ulcerative), pustular, bullous and vegetative. Extracutaneous pulmonary and splenic neutrophilic infiltrates may rarely occur in patients with PG. Despite the paucity of randomized, controlled trials and the lack of a standardized treatment algorithm for PG, systemic corticosteroids and cyclosporine are often used for severe disease.