Necrotizing fasciitis is a life-threatening, invasive soft-tissue infe
ction 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 fasci
itis, anaerobes and gram-negative bacteria are predominant; in the typ
e II form, the bacterial etiology is group A beta-hemolytic streptococ
ci. 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.