Snapshot A 38-year-old man presents to the emergency department for severe pain in his right foot. He reports that these symptoms are accompanied by fever with the leg turning red. He denies any recent trauma but admits to injecting heroin via his lower extremity since he can no longer do so in his arms. Medical history is significant for opioid-use disorder and hepatitis C infection. On physical exam, tenderness to palpation of the affected area is out of proportion to his superficial skin findings. Introduction Clinical definition infection of the superficial fascia that is life threatening Epidemiology risk factors diabetes mellitus chronic corticosteroid use alcohol abuse injection drug use Etiology polymicrobial infection most common (70-80%) contains aerobic and anaerobic organisms aerobes Streptococcus spp. (most common) anaerobes Bacteroides spp. Peptostreptococcus spp. monomicrobial infection most commonly caused by group A Streptococcus Pathogenesis inciting infection at tissue site can be accomplished via hematogenous spread direct inoculation infection rapidly spreads leading to vascular occlusion → ischemia and necrosis crepitus in cases of gas forming organisms (e.g., Clostridium) and anaerobic organisms Prognosis increased mortality and risk of amputation Presentation Symptoms severe pain out of proportion to superficial findings of the affected area fever Physical exam tenderness to palpation palpable crepitus secondary to methane and CO2 production erythema bullae, blisters, or ulcers cutaneous necrosis progression of disease despite antibiotic treatment Studies Labs ↑↑ C-reactive protein ↑ creatine kinase ↑ white blood cell count (BUN) and blood urea nitrogen (BUN) Intraoperative studies Gram stain biopsy Diagnostic criteria based on clinical suspicion and confirmed intraoperatively with surgical debridement labs or imaging do not override clinical judgement Differential Cellulitis Staphylococcus scalded skin syndrome Gas gangrene Treatment Management approach promp surgical debridement is the mainstay of treatment along with antibiotic treatment Medical intravenous empiric antibiotics indication a treatment component of necrotizing fasciitis directed against likely organisms e.g., antibiotics that target group A Streptococcus, gram-negative organisms, anaerobes, and methicillin-resistant Staphylococcus aureus (MRSA) Operative surgical debridement indication a necessary component of treatment that also confirms the diagnosis Complications Streptococcal toxic shock syndrome Compartment syndrome Myositis Muscle necrosis