Snapshot A 45-year-old woman presents to the emergency department for severe pain of her left foot. She states that this has never happened before. Her symptom is accompanied by fever and generalized myalgias. Medical history is significant for type II diabetes mellitus. On physical exam, there is exquisite tenderness to palpation, erythema, palpable crepitus, and tense bullae. Surgery is immediately consulted. 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 the infection rapidly spreads leading to vascular occlusion → ischemia and necrosis crepitus in cases of gas forming organisms (e.g., Clostridium) and anaerobic organisms Presentation Symptoms severe pain out of proportion of 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 Imaging Magnetic resonance imaging (MRI) indication can be helpful to determine the extent of the infection however, it must not delay antibiotics and surgical debridement Studies Labs ↑↑ C-reactive protein ↑ creatine kinase ↑ white blood cell count (WBC) and blood urea nitrogen (BUN) Intraoperative studies Gram stain and culture 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 prompt 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) drugs meropenem or piperacillin-tazobactam and vancomycin or linezolid meropenem or piperacillin-tazobactam covers group A Streptococcus gram-negative organisms anaerobes vancomycin or linezolid covers MRSA penicillin and clindamycin treatment of choice for known group A Streptococcus necrotizing fasciitis Operative surgical debridement indication a necessary component of treatment that also confirms the diagnosis Prognosis Increased mortality and risk of amputation Complications Streptococcal toxic shock syndrome Compartment syndrome Myositis Muscle necrosis