Necrotizing Skin and Soft Tissue Infections Haytham M.A. Kaafarani, MD, MPH*, David R. King, MD INTRODUCTION Necrotizing skin and soft tissue infections (NSSTIs) are severe infections resulting in life-threatening soft tissue destruction and necrosis and resulting from toxin- secreting bacteria. Extensive, rapid, and widespread progression of the infection and necrosis along soft tissue planes is the essential characteristics of the disease. Epidemiology The epidemiology of NSSTIs is not very well established; reliable data on its incidence are largely absent from medical literature, and most published studies reflect Division of Trauma, Emergency Surgery and Surgical Critical Care, Massachusetts General Hos- pital, Harvard Medical School, 165 Cambridge Street, Suite 810, Boston, MA 02114, USA * Corresponding author. E-mail address: hkaafarani@partners.org KEYWORDS  Necrotizing skin and soft tissue infection (NSSTI)  Necrotizing fasciitis  Gas gangrene  Fournier’s gangrene  Wide local debridement KEY POINTS  Necrotizing skin and soft tissue infections (NSSTIs) are caused by aggressive and often toxin-secreting bacteria.  NSSTIs may be caused by single agents such as clostridia or streptococci (type I), but are often polymicrobial (type II).  Immunosuppressed individuals are especially susceptible to NSSTIs.  Systemic signs of infection are ubiquitous, with patients often becoming septic and showing signs of multiorgan dysfunction syndrome.  The Laboratory Risk Indicator for Necrotizing Fasciitis has a high positive and negative predictive value for NSSTIs.  Computed tomography might be helpful in diagnosing NSSTIs, but is often not sufficient to rule it out.  Prompt wide surgical debridement and broad spectrum antibiotics are the key elements needed for successful management and prevention of the high morbidity and mortality associated with NSSTIs. Surg Clin N Am 94 (2014) 155–163 http://dx.doi.org/10.1016/j.suc.2013.10.011 surgical.theclinics.com 0039-6109/14/$ – see front matter Ó 2014 Elsevier Inc. All rights reserved.