Picture of necrotizing fasciitis (flesh-eating disease)

Necrotizing fasciitis is a rare bacterial infection that can destroy skin and the soft tissues beneath it, including fat and the tissue covering the muscles (fascia). Because these tissues often die rapidly, a person with necrotizing fasciitis is sometimes said to be infected with “flesh-eating” bacteria. The most common type of bacteria causing necrotizing fasciitis is streptococcus pyogenes.

Many people who get necrotizing fasciitis are in good health prior to the infection. Those at increased risk of developing the infection are people who:

• Have a weakened immune system or lack the proper antibodies to fight off the infection.
• Have chronic health problems such as diabetes, cancer, or liver or kidney disease.
• Have cuts, including surgical wounds from operations such as an episiotomy or a hernia repair.
• Recently had chickenpox or other viral infections that cause a rash.
• Use steroid medicines, which can lower the body’s resistance to infection.

Symptoms include redness (erythema), swelling (edema) and tenderness. The degree of pain typically is greater than the severity of these findings and the person appears terribly ill. The original skin wound is often evident. Skin changes may include bullous lesions (blisters) and local skin anesthesia (due to blocking of little vessels in the skin). A crinkly or crackling feeling called crepitus indicates gas in the tissues but occurs in only about half of cases.

Treatment of necrotizing fasciitis is most effective if the infection is recognized in time. Antibiotics and surgical removal of dead tissue are required. If the tissue destruction is widespread, extensive surgery or amputation might be the only way to prevent death.

Top: cellulitis of the left forearm; Bottom: necrotizing fasciitis of the left leg

While early diagnosis and treatment are the key to preventing devastating tissue destruction, physicians and patients often fail to recognize necrotizing fasciitis and its severity.

Being rare, and with an onset that resembles flu-like symptoms, it is often missed until the infection has advanced. One alerting sign is unusually severe pain – far greater than normal for a cut or wound – and painful lymph nodes. For example, a cut on the toe or a surgical leg wound, followed some hours later by severe pain either in the toe, leg, or in the groin (as the infection travels to the lymph nodes), can warn of this potentially deadly, fast-spreading infection.