summary Necrotizing Fasciitis is a life-threatening bacterial soft tissue infection that spreads along soft tissue planes rapidly. Diagnosis is made clinically with the presence of skin discoloration, bullae, palpable crepitus and calculation of the LRINEC score. Emergent frozen section can help confirm diagnosis in early cases. Treatment is emergent radical debridement of all devitalized tissues with broad-spectrum IV antibiotics. Epidemiology Risk factors immune suppression login to view 4 more bullets bacterial introduction login to view 5 more bullets Etiology Associated conditions cellulitis login to view 1 more bullet Classification Necrotizing Fasciitis Classification Type Organism Characteristics Type 1 Polymicrobial Typically 4-5 aerobic and anaerobics pecies cultured: Non-Group A Strep Anaerobes including Clostridia Facultative anaerobes Enterobacteria Synergistic virulence between organisms Most common (80-90%) Seen in immunosuppressed (diabetics and cancer patients) Postop abdominal and perineal infections Type 2 Monomicrobial Group A β-hemolytic Streptococci is most common organism isolated 5% of cases Seen in healthy patients Extremities Type 3 Marine Vibrio vulnificus (gram negative rods) Marine exposure Type 4 Fungal Presentation Symptoms early login to view 3 more bullets late findings login to view 3 more bullets Physical exam skin bullae discoloration login to view 2 more bullets swelling, edema dermal induration and erythema subcutaneous emphysema (gas producing organisms) Imaging Radiographs not required for diagnosis or treatment Studies Biopsy indications login to view 1 more bullet technique login to view 3 more bullets histological findings login to view 4 more bullets LRINEC Scoring system Components login to view 16 more bullets Literature login to view 2 more bullets Differentials Gas gangrene Treatment Operative emergent radical debridement and broad-spectrum IV antibiotics login to view 21 more bullets amputation login to view 2 more bullets Prognosis Life threatening infection mortality rate of 32% login to view 1 more bullet mortality correlates with time to surgical intervention