Conditions Basics

What is necrotizing fasciitis (flesh-eating bacteria)?

Necrotizing fasciitis is an infection caused by bacteria. It can destroy skin, fat, and the tissue covering the muscles within a very short time.

The disease sometimes is called flesh-eating bacteria. When it occurs on the genitals, it is called Fournier gangrene.

Necrotizing fasciitis is very rare but serious. Many people who get necrotizing fasciitis are in good health before they get the infection.

Your risk of getting this infection is higher if you:

• Have a weak immune system.
• Have chronic health problems such as diabetes, cancer, or liver or kidney disease.
• Have cuts in your skin, including surgical wounds.
• Recently had chickenpox or other viral infections that cause a rash.
• Use steroid medicines, which can lower the body's resistance to infection.

What causes it?

Necrotizing fasciitis is caused by several kinds of bacteria. Some of these bacteria also cause infections such as strep throat and impetigo. Usually the infections caused by these bacteria are mild. But in rare cases they can cause necrotizing fasciitis. This is a more dangerous infection.

You can get necrotizing fasciitis when bacteria enter a wound, such as from an insect bite, a burn, or a cut. It is not as common, but you can also get it in:

• Wounds that come in contact with seawater or fresh water. Or you can get it by eating contaminated oysters.
• An intestinal surgery site, or in tumours or other injuries in the intestines.
• A muscle strain or bruise, even if there is no break in the skin.

It is very rare for someone to spread necrotizing fasciitis to another person.

What are the symptoms?

The symptoms often start suddenly after an injury. You may need medical care right away if you have pain that gets better over 24 to 36 hours and then suddenly gets worse. The pain may be much worse than you would expect from the size of the wound or injury. You may also have:

• Skin that is red, swollen, and hot to the touch.
• A fever and chills.
• Nausea and vomiting.
• Diarrhea.

The infection may spread rapidly. It quickly can become life-threatening. You may go into shock and have damage to skin, fat, and the tissue covering the muscles. (This damage is called gangrene.) Necrotizing fasciitis can lead to organ failure and death.

How is it diagnosed?

The doctor will diagnose your infection based on how suddenly your symptoms started and how quickly the infection is spreading. The infected tissue may be tested for bacteria. You also may need X-rays, a CT scan, or an MRI to look for injury to your organs or to find out how much the infection has spread.

How is necrotizing fasciitis treated?

Early treatment of necrotizing fasciitis is critical. The sooner treatment begins, the more likely you will recover from the infection and avoid serious complications, such as limb amputation or death. You may be treated in the intensive care unit (ICU) at the hospital.

Treatment may include:

• Surgery that removes infected tissue and fluids to stop the spread of infection. Surgery is almost always needed. Most people need several surgeries to control the infection. Removing limbs (amputation) or organs may be done to save the person's life, depending on how severe the infection is and where it has spread.
• Medicines (such as antibiotics). These kill the bacteria causing the infection.
• Procedures to treat complications such as shock, breathing problems, and organ failure.
• Hyperbaric oxygen therapy.

How can you prevent it?

Necrotizing fasciitis is very rare. Bacteria that cause the disease usually don't cause infection unless they enter the body through a cut or other break in the skin.

If you've been in close contact with someone who has necrotizing fasciitis, and you notice any symptoms of infection (such as pain, swelling, redness, or fever), see your doctor right away.

To help prevent any kind of infection, wash your hands often. And always keep cuts, scrapes, burns, sores, and bites clean.