Necrotizing fasciitis.

Necrotizing fasciitis is a life-threatening, invasive soft-tissue infection that is characterized by widespread, rapidly developing necrosis of the subcutaneous tissue and fascia. It is more likely to occur in patients with a compromised immune system. In type I necrotizing fasciitis, anaerobes and gram-negative bacteria are predominant; in the type II form, the bacterial etiology is group A beta-hemolytic streptococci. The diagnosis must be made on the basis of clinical grounds and is characterized by rapidly developing, painful erythema that progresses to bullous formation and gangrenous necrosis.