[Management of pyoderma gangrenosum. An update on clinical features, diagnosis and therapy].

Pyoderma gangrenosum is a rare neutrophilic inflammatory skin disease, mostly observed in middle-aged adults. Etiology and pathogenesis remain unclear. Autoimmune mechanisms including immune complex-mediated neutrophilic vascular reactions have been suggested. The hallmark finding in pyoderma gangrenosum is painful ulcers with sharply circumscribed and demarcated, frequently undermined, livid borders and a necrotic base. Pyoderma gangrenosum has been described in association with a great variety of systemic disorders, ranging from inflammatory bowel diseases to myeloproliferative disorders. The diagnosis of pyoderma gangrenosum is based primarily on the clinical presentation and course. It is usually a diagnosis of exclusion. Histopathological and laboratory findings in pyoderma gangrenosum are nonspecific. The aims of therapy are the complete suppression of inflammatory disease activity, promotion of wound healing and control of pain. Frequently, successful treatment of associated diseases leads to an improvement or complete remission of pyoderma gangrenosum. Surgical interventions, including aggressive ulcer excision, recipient site preparation and autologous skin grafting have to be avoided during the active phase of the disease because the likely occurrence of pathergy inducing new lesions at surgical sites and causing a worsening the original lesions.