Necrotizing fasciitis is a rare but potentially life-threatening bacterial infection. It affects the tissue surrounding muscle (fascia). The affected tissue dies (necrosis), preventing cells of the immune system from reaching the site of the infection and allowing bacteria to spread rapidly. This extremely dangerous illness can quickly lead to death if not promptly and effectively treated.

Necrotizing fasciitis is sometimes caused by group A streptococci. However, other types of bacteria may also cause necrotizing fasciitis. Most often, infection results from skin wounds or abrasions contaminated with dirt or debris.

The earliest signs of necrotizing fasciitis are often pain and unexplained fever. A small, reddish painful spot may develop on the skin, which may become tender, swollen and warm to the touch. Blue or purple blisters may appear that contain a brown fluid that is watery and may be foul-smelling.

As the infection progresses, the skin may change to black as tissue death occurs. The infection may quickly spread to other parts of the body and cause a decrease in blood pressure, shock and multi-organ failure. Patients may lose consciousness.

Necrotizing fasciitis progresses very rapidly, often within just a few hours. Immediate medical treatment is necessary to prevent serious health consequences, including death. Blood cultures or aspiration of pus from the affected tissue can help confirm a diagnosis of necrotizing fasciitis. However, patients often undergo intravenous treatment with antibiotics in cases of suspected necrotizing fasciitis – even before certain diagnostic tests (e.g., blood tests, tissue analyses) can confirm the diagnosis. The affected tissue must also be removed. In some cases, limb amputation may be necessary to prevent the spread of infection. Even with prompt treatment, fatality rates remain high.

People can reduce their risk of contracting necrotizing fasciitis by taking several basic steps. For example, good hygiene can reduce contamination with bacteria that may cause this illness. Keeping wounds clean and watching for signs of infection can help reduce the likelihood of contracting necrotizing fasciitis.