How is necrotizing fasciitis diagnosed?
Often a preliminary diagnosis of necrotizing fasciitis is based on the patient’s symptoms, including the medical and exposure history as described above. For example, a diabetic patient with a rectal fistula that develops pain, swelling, and scrotal skin changes may be preliminarily diagnosed with Fournier’s gangrene, while another diabetic patient with liver failure and skin changes (bullae) and exposure to seawater may be preliminarily diagnosed with a Vibrio vulnificus infection. Initial treatment is often begun based upon a preliminary diagnosis because waiting for a definitive diagnosis can delay treatment and result in increased morbidity and mortality. Gram staining of exudates (fluid from the infection site) or biopsied tissue may provide the physician clues to determine what organism(s) are causing the infection. For example, the stain can distinguish between Gram-negative and Gram-positive organisms and further distinguish their shapes (coccus or round, rod, or comma-shaped l
