[What data is needed today to deal with cellulitis and necrotizing fasciitis?].

Cellulitis and necrotizing fasciitis can be distinguished by the depth of the cutaneous lesion and classically by the different bacteria implicated. This classification is not taken into account by the practitioner because of a similar therapeutic strategy. That is why most authors used a single title: necrotizing soft tissue infection. The potential severity of these infections required a quick diagnosis to decrease the risk of mortality and severe functional consequences. The analysis of the literature doesn't allow to establish the incidence of these infections. It was demonstrated that infections due to Streptococcus serogroup A increased over the last few years, thanks to a specific surveillance system. Risk factors leading to these infections are: cutaneous trauma, age, diabetes, varicella in children, contact with people infected by Streptococcus. The most recent studies demonstrated a frequent polymicrobism of the infections, with anaerobes, Streptococcus, Staphylococcus, and gram-negative rods. At the onset of the disease, the diagnosis is difficult to establish. Pain, induration of tissues, a rapid evolution, the inefficacy of antibiotic treatment suggest the diagnosis of necrotizing infection. MRI, when available, is a good technique to reveal the depth of the infection and necrosis. Surgery will confirm the diagnosis and allow for debridement of necrotized tissues. A delayed surgery increases the mortality risk factor, as stated in numerous studies.