[Pyoderma gangrenosum after orthopedic conservative treatment].

Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis. Half of the cases are associated with an immune dysfunction and are frequently triggered by pathergy such as a tissular aggression via surgery or burn wounds. A patient with ulcerative colitis presented a PG at the site of an iontophoresis patch for tendinopathy. Treatment in a specialized burn center, corticosteroid therapy and adapted local care contributed to a favourable evolution. PG remains a diagnosis of exclusion and inflammatory phenomena must be differentiated from infectious causes such as necrotizing fasciitis to initiate immunosuppressive treatment. Being rare and difficult to diagnose and to treat as well as associated with potentially severe sequelae, a multidisciplinary team is required for the management of PG.