What Is Necrotizing Fasciitis?

By Katharine Paljug @kpaljug
September 25, 2017

Have you heard of flesh-eating bacteria, but are wondering what is necrotizing fasciitis? They’re the same. Read more about the symptoms.

What is necrotizing fasciitis?

Necrotizing fasciitis is a dangerous and potentially fatal skin infection. It is caused by bacteria that spreads rapidly and kills your soft tissue cells. Necrotizing fasciitis requires prompt medical treatment with antibiotics, and sometimes surgery is necessary to stop the spread of the bacteria. If left untreated, the infection can lead to toxic shock syndrome, sepsis, organ failure, and death.

Originally called hospital gangrene, necrotizing fasciitis was first described by doctors in 1871. It is very rare, and most people have a strong enough immune system to fight off this sort of infection. The people who get necrotizing fasciitis usually have other health problems that compromise their immune system, such as diabetes, cancer, kidney disease, or other severe chronic illnesses. It is rare that one person will spread necrotizing fasciitis to another.

A review of research on necrotizing fasciitis concluded that it is “prevalent enough that most primary care physicians will be involved with managing at least [one] case during their time in practice, but infrequent enough for most to be unfamiliar with the disease.”

You may know necrotizing fasciitis by its more common and sensational name: flesh-eating bacteria.


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What is flesh-eating bacteria?

There are multiple bacteria that can cause necrotizing fasciitis, all of which can be given the label “flesh-eating” bacteria.

These include Staphylococcus aureus, or staph, E coli, Klebsiella, Bacteroides, Clostridium, and group A Streptococcus, or group A strep.

Though group A strep is the most common type of flesh-eating bacteria, most of the infections it causes are mild and easily treated, never becoming necrotizing fasciitis.

Similarly, the other types of flesh-eating bacteria are more likely to cause other, less dangerous diseases. Some live in the body permanently, like Bacteroides, which is found in your digestive system and usually prevents more serious pathogens from causing infections.

When these bacteria infect your soft tissue, however, they can become dangerous. Flesh-eating bacteria usually enter through a cut, burn, or surgical site in your skin, though some can spread from punctured organs. When this happens, the bacteria release toxins that cut off blood supply to your tissue. Because white blood cells are key to fighting infection, your immune system has no way of responding to the bacteria, and your soft tissue cells begin to die rapidly.

Necrotizing soft tissue infection

Necrotizing fasciitis is a type of necrotizing soft tissue infection, or NSTI.

Necrotizing means “causing the death of tissue.” Fasciitis refers to the fascia, or the connective tissue that surrounds the nerves, blood cells, muscles, and fat in your body. Necrotizing fasciitis is a necrotizing soft tissue infection that affects the fascia.

Other kinds of NSTIs include necrotizing adipositis, necrotizing cellulitis, and necrotizing myositis, all of which affect different soft tissues in the body. Medical researchers are encouraging doctors to use the umbrella term necrotizing soft tissue infection when describing any of these diseases, as the symptoms and course of treatment for all of them are similar.

However, both necrotizing fasciitis and flesh-eating bacteria are more commonly used and recognized terms for necrotizing soft tissue infections.

Flesh-eating bacteria symptoms

The Centers for Disease Control and Prevention (CDC) warns that initial flesh-eating bacteria symptoms can be hard to spot. Symptoms usually begin immediately after an injury or surgery and include pain or aching at the site of the wound, similar to the feeling of a pulled muscle.

You may also notice swelling and a red or purplish color around the wound that rapidly expands across your skin. As the infection spreads, other symptoms include:

  • Ulcers, blisters, or red lumps on the skin
  • Black spots with dead skin at the center
  • Grey or smelly liquid draining from a wound
  • Areas around a wound that feel hot or numb
  • Severe pain
  • Fever, chills, and excessive sweating
  • Lightheadedness or confusion
  • Vomiting
  • Fatigue

If you have these symptoms after an injury or surgery, the CDC warns that you should seek medical attention immediately, as the window for successfully treating flesh-eating bacteria is very narrow.


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March 26, 2020

Reviewed By:  

Janet O’Dell, RN