Necrotizing Fasciitis (Flesh-Eating Bacteria)

Necrotizing fasciitis is a rare infection that's often described in media reports as a condition involving "flesh-eating bacteria." It can be fatal if not treated promptly.

Necrotizing fasciitis spreads quickly and aggressively in an infected person. It causes tissue death at the infection site and beyond.

Every year, between 600 and 700 cases are diagnosed in the U.S. About 25% to 30% of those cases result in death. It rarely occurs in children.

How Do You Get Necrotizing Fasciitis?

The bacteria that cause necrotizing fasciitis can enter the body following surgery or injury. They can also enter the body through:

In some cases, it is unknown how the infection began. Once it takes hold, the infection rapidly destroys muscle, skin, and fat tissue.

Causes of Necrotizing Fasciitis

Necrotizing fasciitis is commonly caused by group A Streptococcus (GAS) bacteria. That's the same type of bacteria that causes strep throat. However, several types of bacteria, such as staphylococcus and others, have also been associated with the disease.

Necrotizing fasciitis occurs when such bacteria infect the superficial fascia, a layer of connective tissue below the skin.

Symptoms of Necrotizing Fasciitis

The symptoms of necrotizing fasciitis usually occur within the first 24 hours of infection. They often include a combination of the following:

  • Increasing pain in the general area of a minor cut, abrasion, or other skin opening.
  • Pain that is worse than would be expected from the appearance of the cut or abrasion.
  • Redness and warmth around the wound, though symptoms can begin at other areas of the body.
  • Flu-like symptoms such as diarrhea, nausea, fever, dizziness, weakness, and general malaise.
  • Intense thirst due to dehydration.

More advanced symptoms occur around the painful infection site within three to four days of infection. They include:

  • Swelling, possibly accompanied by a purplish rash.
  • Large, violet-colored marks that transform into blisters filled with dark, foul-smelling fluid.
  • Discoloration, peeling, and flakiness as tissue death (gangrene) occurs.

Critical symptoms, which often occur within four to five days of infection, include:


Diagnosis of Necrotizing Fasciitis

Necrotizing fasciitis progresses very rapidly, making early diagnosis crucial.

Unfortunately, that does not always occur. The early symptoms of an infection with flesh-eating bacteria are similar to other conditions like the flu or a less serious skin infection. The early symptoms are also similar to common post-surgical complaints, such as:

Diagnosis is often based on advanced symptoms, such as the presence of gas bubbles under the skin. Laboratory analysis of fluid and tissue samples is done to identify the particular bacteria that are causing the infection. Treatment, however, begins before the bacteria are identified.

Household members and others who have had close contact with someone with necrotizing fasciitis should be evaluated if they develop symptoms of an infection.

Necrotizing Fasciitis Treatment

Patients infected with flesh-eating bacteria will undergo several types of treatment. The extent of treatment depends on the stage of the disease when treatment is started. The treatment includes:

  • Intravenous antibiotic therapy.
  • Surgery to remove damaged or dead tissue in order to stop the spread of infection.
  • Medications to raise blood pressure.
  • Amputations of affected limbs, in some cases.
  • Hyperbaric oxygen therapy may be recommended to preserve healthy tissue.
  • Cardiac monitoring and breathing aids.
  • Blood transfusions.
  • Intravenous immunoglobulin. This supports the body's ability to fight infection.

WebMD Medical Reference Reviewed by Carol DerSarkissian on July 30, 2018



Medscape: "Necrotizing Fasciitis Clinical Presentation," "Emergent Management of Necrotizing Fasciitis."

Merck Manuals: "Necrotizing Skin Infections."

CDC: "Group A Streptococcal (GAS) Disease."

National Necrotizing Fasciitis Foundation: "Necrotizing Fasciitis Factsheet."

American College of Chest Physicians: "Necrotizing Fasciitis and Deep Soft Tissue Infections in the ICU."

© 2018 WebMD, LLC. All rights reserved.