Necrotizing Fasciitis: All You Need to Know

Nurses make leg ulcers in emergency room.

Necrotizing fasciitis (NECK-re-tie-zing FASH-e-i-tis) is a rare bacterial infection that spreads quickly in the body and can cause death. Accurate diagnosis, rapid antibiotic treatment, and prompt surgery are important to stopping this infection. See a doctor right away if you have a fever, dizziness, or nausea soon after an injury or surgery.

Group A Strep Thought to Be Most Common Cause

Although media reports often call it “flesh-eating bacteria,” more than one type of bacteria can cause necrotizing fasciitis. Public health experts believe group A Streptococcus (group A strep) are the most common cause of necrotizing fasciitis. This web page only focuses on necrotizing fasciitis caused by group A strep bacteria.

Breaks in the Skin Can Allow Bacteria to Enter

The bacteria most commonly enter the body through a break in the skin, including:

  • Cuts and scrapes
  • Burns
  • Insect bites
  • Puncture wounds (including those due to intravenous or IV drug use)
  • Surgical wounds

However, people can also get necrotizing fasciitis after an injury that does not break the skin (blunt trauma).

What’s in a Name?

Necrotizing means causing the death of tissues. Fasciitis means inflammation of the fascia (the tissue under the skin that surrounds muscles, nerves, fat, and blood vessels).

Symptoms Can Often Be Confusing and Develop Quickly

The infection often spreads very quickly. Early symptoms of necrotizing fasciitis can include:

  • A red or swollen area of skin that spreads quickly
  • Severe pain, including pain beyond the area of the skin that is red or swollen
  • Fever

See a doctor right away if you have these symptoms after an injury or surgery. Even though minor illnesses can cause symptoms like these, people should not delay getting medical care.

Later symptoms of necrotizing fasciitis can include:

  • Ulcers, blisters, or black spots on the skin
  • Changes in the color of the skin
  • Pus or oozing from the infected area
  • Dizziness
  • Fatigue (tiredness)
  • Diarrhea or nausea
Prompt Treatment Is Key
Photo of an iv taped to the top of a hand

Doctors treat necrotizing fasciitis with IV antibiotics.

Necrotizing fasciitis is a very serious illness that requires care in a hospital. Antibiotics and surgery are typically the first lines of defense if a doctor suspects a patient has necrotizing fasciitis.

Since necrotizing fasciitis can spread so rapidly, patients often must get surgery done very quickly. Doctors also give antibiotics through a needle into a vein (IV antibiotics) to try to stop the infection.

Sometimes, however, antibiotics cannot reach all of the infected areas because the bacteria have killed too much tissue and reduced blood flow. When this happens, doctors have to surgically remove the dead tissue. It is not unusual for someone with necrotizing fasciitis to end up needing multiple surgeries. In serious cases, the patient may need a blood transfusion.

Diagnosis Can Be Difficult and Acting Fast Is Key

There are many infections that look similar to necrotizing fasciitis in the early stages, which can make diagnosis difficult. In addition to looking at the injury or infection, doctors can diagnose necrotizing fasciitis by:

  • Taking a tissue sample (biopsy)
  • Looking at bloodwork for signs of infection and muscle damage
  • Imaging (CT scan, MRI, ultrasound) of the damaged area

However, it is important to start treatment as soon as possible. Therefore, doctors may not wait for test results if they think a patient might have necrotizing fasciitis.

Silhouette people.

Up to 1 in 3 people with necrotizing fasciitis die from the infection.

Serious Complications Are Common

Necrotizing fasciitis can lead to sepsis, shock, and organ failure. It can also result in life-long complications from loss of limbs or severe scarring due to surgically removing infected tissue. Even with treatment, up to 1 in 3 people with necrotizing fasciitis die from the infection. Six out of every 10 people who get both necrotizing fasciitis and streptococcal toxic shock syndrome at the same time die from their infections. Streptococcal toxic shock syndrome is another very serious illness caused by group A strep. It causes the body to go into shock and involves low blood pressure and multiple organ failure.

While Rare, Some People Are More Likely to Get Necrotizing Fasciitis

While anyone can get necrotizing fasciitis, it is rare. Most people who get this illness have other health problems that may lower their body’s ability to fight infections. Some conditions that weaken the body’s immune system include:

  • Diabetes
  • Kidney disease
  • Scarring (cirrhosis) of the liver
  • Cancer

Necrotizing fasciitis can also be a rare complication of chickenpox in young children.

Necrotizing Fasciitis Is Rarely Contagious

Most cases of necrotizing fasciitis occur randomly. It is very rare for someone with necrotizing fasciitis to spread the infection to other people. For this reason, doctors usually do not give preventive antibiotics to close contacts of someone with necrotizing fasciitis.

Good Wound Care Helps Prevent Skin Infections

First Aid leg injury wash with soap and water.

Use soap and water to clean all minor cuts and injuries.

Common sense and good wound care are the best ways to prevent a bacterial skin infection.

  • Clean all minor cuts and injuries that break the skin (like blisters and scrapes) with soap and water.
  • Clean and cover draining or open wounds with clean, dry bandages until they heal.
  • See a doctor for puncture and other deep or serious wounds.
  • Wash hands often with soap and water or use an alcohol-based hand rub if washing is not possible.
  • Care for fungal infections like athlete’s foot.

If you have an open wound or skin infection, avoid spending time in:

  • Hot tubs
  • Swimming pools
  • Natural bodies of water (e.g., lakes, rivers, oceans)

There are no vaccines to prevent group A strep infections, including necrotizing fasciitis.

CDC Tracks Necrotizing Fasciitis Caused by Group A Strep

CDC tracks necrotizing fasciitis caused by group A strep with a special system called Active Bacterial Core surveillance (ABCs). Since 2010, approximately 700 to 1200 cases occur each year in the United States. This is likely an underestimate. According to ABCs data, the number of annual group A strep necrotizing fasciitis infections reported to ABCs does not appear to be rising.