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.

Necrotizing fasciitis is a rare but potentially life-threatening bacterial infection of deep layers of tissue that surround muscle. It occurs when bacteria enter a person’s body through a skin injury or abrasion. In one recent year (1999), 600 cases of necrotizing fasciitis were diagnosed in the United States, according to the U.S. Centers for Disease Control and Prevention.

In most types of skin infection,  white blood cells and antibodies travel through the blood to the infection site and fight the invading organisms and protect the skin and nearby tissues. However, after the bacteria associated with necrotizing fasciitis begin to grow, they release toxins that cause clotting of small blood vessels in the infected area. This obstructs blood flow to the tissue, resulting in tissue death (necrosis).

Because blood no longer flows to this tissue, the white blood cells and antibodies cannot fight the infection. This enables the bacteria to thrive as they digest materials in the tissue and spread rapidly deep in the skin along the surface of the muscle (fascia).

Left untreated, necrotizing fasciitis can quickly lead to death. It is an extremely dangerous infection, and the success of treatment efforts varies depending on the type of infecting organism, the rate of the infection’s spread, the infection’s susceptibility to antibiotics and how quickly the condition is diagnosed and treated. Even with prompt treatment, fatality rates remain high.

Prompt treatment is vital to a patient’s changes of survival. For this reason, patients are urged to clean any skin injury thoroughly and to consult a physician if they spot signs of infection such as redness, pain, drainage or swelling around a wound.

Necrotizing fasciitis resembles necrotizing cellulitis, a potentially serious bacterial infection of connective tissue. However, in addition to affecting deeper skin layers, necrotizing fasciitis also differs from necrotizing cellulitis in that it typically involves more pain and is marked by significant systemic toxicity. Necrotizing fasciitis may occur in tandem with necrotizing myositis, in which infection also involves muscle tissue.

Necrotizing fasciitis is most commonly caused by bacteria known as group A streptococci, also sometimes referred to as “flesh-eating bacteria,” although it is the toxins released by the bacteria that kill the tissue. Other types of bacteria can also cause necrotizing fasciitis. Both oxygen-using (aerobic) bacteria and oxygen-avoiding (anaerobic) bacteria can cause this disease. Group A streptococci also cause many milder infections, such as strep throat and impetigo.

Most often, infection results from skin wounds or abrasions contaminated with dirt or debris. In some cases, surgical incisions may be the source of infection. It is possible for infection to penetrate through even healthy skin. Some conditions (e.g., diverticulitis, intestinal perforation or tumor) may involve bacteria that escapes from the intestine and spreads to tissue that surround muscle, causing necrotizing fasciitis to develop in the abdominal wall, genital area or thighs. Other conditions that may lead to necrotizing fasciitis include hemorrhoids, anal fissures or urethral tears.

Those people at greater risk for contracting necrotizing fasciitis include people with compromised immune systems, other chronic illnesses (e.g., cancer, diabetes, kidney disorders) or who are taking medications that suppress the immune system (e.g., corticosteroids). The infection is also more likely to occur in older patients than in younger patients.

The earliest signs of necrotizing fasciitis are often pain and unexplained fever. A small, reddish spot may develop on the skin. This reddened area may be tender, warm and swollen, and may develop into larger bronze or purplish patches. Blisters may develop that contain fluid that is brown, watery and sometimes foul-smelling. Pain may become severe. As the infection progresses, the skin may turn black as tissue death (necrosis) occurs. Gas may form under the skin, causing the affected area to feel crackly. The visual expansion of symptoms may occur in as little as an hour.

As the skin dies, the nerves cease to work and pain may dissipate. 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.

Other symptoms that may accompany necrotizing fasciitis include:

• Chills
• Confusion
• Dizziness
• Nausea
• Profound weakness
• Sweating

Necrotizing fasciitis progresses very rapidly, often within just a few hours. Immediate medical treatment is necessary to prevent serious health consequences, including death.

Prompt treatment of suspected cases of necrotizing fasciitis is crucial. This usually involves administering antibiotics intravenously. Antibiotics may be started before certain diagnostic tests (e.g., blood tests, tissue samples) can confirm the diagnosis. Aggressive surgical debridement, in which the infected tissue (e.g., skin, fat, muscle) is removed, is required. The affected areas also are drained.

In some cases, limb amputation may be necessary if the infection cannot be controlled. In addition, skin grafting may be required if large amounts of tissue were removed during debridement.

Pooled immunoglobulins (antibodies) may be given intravenously to fight the infection. In cases where anaerobic (oxygen-avoiding) bacteria are responsible for the infection, the patient may be placed in a hyperbaric oxygen chamber. This is a device in which patients receive 100 percent oxygen at different atmospheres of pressure.

Preparing questions in advance can help patients have more meaningful discussions regarding their conditions. Patients may wish to ask their doctor the following questions related to necrotizing fasciitis:

1. How can I prevent necrotizing fasciitis?
   
   
2. How will I know if my symptoms indicate the possible presence of necrotizing fasciitis?
   
   
3. Should I call a doctor if something appears wrong, or should I immediately go to an emergency room?
   
   
4. Is there anything I should or shouldn’t do from the time I discover the problem until I get to the emergency room?
   
   
5. What type of antibiotic are you going to administer? What is the success rate of treatment using this drug?
   
   
6. How much skin and tissue will you likely have to remove?
   
   
7. Is it possible that you will need to amputate a limb?
   
   
8. Will I require skin grafting?
   
   
9. Are there signs I should watch for following treatment that might indicate that some of the infection has not been eliminated?
   
   
10. Is treatment in a hyperbaric oxygen chamber likely to help my condition?