[Pyoderma gangrenosum: pathogenesis, diagnosis, and treatment].

Pyoderma gangrenosum (PG) is a skin disease that rapidly develops from papules or primarily sterile pustules. It is characterized by the formation of extremely painful wounds with a reddish-livid edge and surrounding areas. It can be triggered by trauma, bacteria or drugs in genetically predisposed people. In 70% of cases, the predilection sites manifest at the extensor sides of the lower extremities. Although the exact pathophysiology of this rare neutrophilic dermatosis has not yet been fully elucidated, an autoinflammatory genesis with increased neutrophil granulocyte activity is currently being discussed. Patients often have inflammatory comorbidities such as chronic inflammatory bowel disease or cancer. To confirm the diagnosis, the validated PARACELSUS score, which summarizes the nonspecific criteria, should be used. In addition to the administration of immunosuppressive drugs such as prednisolone and/or ciclosporin, patients with proven PG are treated systemically with biologics, small molecules, or intravenous immunoglobulins. Utilization of these pharmaceutical agents has seen a marked increase in recent cases of PG. This should be accompanied by topical pharmacological treatment of the wound surroundings as well as modern wound and pain therapy.