Clinical criteria and risk factors.

Necrotizing cellulitis and fasciitis may be difficult to recognize. When sk in necrosis is not obvious, the diagnosis must be suspected if there are si gns of severe sepsis (accelerated heart or respiratory rates, aiguria, ment al confusion...) and/or same of the following local symptoms or signs: seve re spontaneous pain. Indurated edema, bullae, cyanosis, skin pallor, absenc e of lymphangitis, skin hypoesthesia, crepitation, muscle weakness, foul sm ell of exudates, Many risk factors are suspected. A recent case control stu dy demonstrated that using ibuprofen increased the risk of cellulitis compl icating chickenpox in children. Evidence is lower for other risk factors th at are present with a high prevalence in most series: local lesion of skin or mucous membranes (acute or chronic disease, traumatism, surgery...), dia betes, arteriopathy, alcoholism, obesity, immunosuppression, NSAIDs. The ri sk of streptococcal necrotizing fasciitis is increased when in contact with patients infected by the same streptococcus.