Necrotizing fasciitis: How reliable are the cutaneous signs?

Necrotizing fasciitis (NF) is a surgical emergency. It is often aggressive and characterized by the rapidly progressive inflammatory infection of the fascia that causes extensive necrosis of the subcutaneous tissue and fascia, relatively sparing the muscle and skin tissue. As the disease progresses, thrombosis of the affected cutaneous perforators subsequently devascularizes the overlying skin. The course indeed can be a fulminant one. The diagnosis of NF, especially in the early stages, is extremely challenging, and it can be very close in presentation to other skin and subcutaneous tissue infections. The primary site of the pathology is the deep fascia. Necrosis of the tissues and fascia may manifest as erythema without sharp margins, swelling, warmth, shiny, and exquisitely tender areas. Pain out of proportion to physical examination findings may be observed. The subcutaneous tissue may be firm and indurated such that the underlying muscle groups cannot be distinctly palpated. Eventually, as the overlying skin is stripped of its blood supply, skin necrosis ensues and hemorrhagic bullae form. Bacteremia and sepsis invariably develop when the infection is well established. This paper discusses some of issues related to the cutaneous signs found in NF and also provides a review the current, available literature on the subject matter.