Blunt Trauma as a Risk Factor for Group A Streptococcal Necrotizing Fasciitis

Purpose Anecdotal reports suggest that blunt trauma and seemingly innocuous musculoskeletal injuries (e.g., muscle strains) are risk factors for developing necrotizing fasciitis (NF) and myositis caused by group A Streptococcus and other bacteria; however, this hypothesis has not been tested in analytic epidemiologic studies of invasive group A streptococcal (GAS) disease. We conducted two case–control studies to determine whether nonpenetrating trauma is a risk factor for either NF or severe cellulitis caused by GAS. Methods A secondary analysis of patients who were hospitalized throughout Florida for invasive GAS disease during a 4-year period was conducted. Two case series were used. The first series comprised patients who had severe GAS cellulitis. The second were patients who had GAS NF. Case-patients were compared to a single control series composed of patients with invasive GAS disease not including either NF or cellulitis (e.g., primary bacteremia, septic arthritis). Results After we adjusted for age, race, and clindamycin usage, GAS NF cases were 5.97 times as likely as controls to have a recent history of blunt trauma (p = 0.04). Patients with severe cellulitis were not more likely than controls to have associated blunt trauma. Conclusions Nonpenetrating trauma is significantly associated with the development of GAS NF.