[Pyoderma gangrenosum].

Pyoderma gangrenosum is a diagnostic and therapeutic challenge. A misdiagnosis or delayed diagnosis can lead to increased morbidity and death. A fast workup and initiation of treatment is essential. In this review, we present new diagnostic criteria, which can ease the diagnosis, and we summarise the evidence of different treatment modalities. The evidence points towards local immunosuppressive treatment in mild disease, supplemented by systemic glucorticosteroids, ciclosporin or tumour necrosis factor-alpha inhibitors in severe cases. Other biologics are emerging.