Severe skin and soft tissue infections and associated critical illness.

Skin and soft tissue infections (SSTIs) span a broad spectrum of clinical entities from limited cellulitis to rapidly progressive necrotizing fasciitis, which may be associated with septic shock or a toxic shock-like syndrome. These infections may manifest initially as pyodermas that then progress; alternatively, they may arise from metastatic spread of microorganisms from a distant focus. Regardless of the source, SSTIs may lead to critical illness. The complex interplay of environment, host, and pathogen are important to consider when evaluating SSTIs and planning appropriate therapy. The keys to a successful outcome are early identification of risk factors for specific pathogens and early initiation of empiric antimicrobial therapy. For certain types of SSTIs, surgical intervention for diagnosis and/or therapy is also required.