Health Library


What is gangrene?

Gangrene is a dangerous and potentially fatal condition that happens when the blood flow to a large area of tissue is cut off. This causes the tissue to breakdown and die. Although gangrene often turns the affected skin a greenish-black color, the word gangrene is not related to green, but rather to the condition itself. It comes from Greek and Latin words for a gnawing sore or decayed tissue. 

What causes gangrene?

Gangrene happens when blood supply to certain tissues is stopped due to an infection, an injury such as a burn or combat wound, or a chronic disease. Chronic diseases that harm the circulatory system include diabetes, peripheral artery disease, and Raynaud's disease. These can often lead to gangrene. Traumatic injuries like burns or an infected dog bite may also stop blood flow. Severe cases of frostbite can also lead to gangrene. Frostbite is a condition in which the skin freezes.

What are the risk factors for gangrene?

People with diabetes, peripheral artery disease, and Raynaud’s disease are at higher risk for gangrene. Skin infections, injuries, burns, dog bites, and frostbite also put people at risk for gangrene.

What are the symptoms of gangrene?

Symptoms of gangrene depend on its location and cause. Dry gangrene usually starts with a red line around the affected area. This area then turns black.

These are other symptoms of gangrene:

  • Coldness and numbness in the affected area
  • Pain in or beyond the affected area
  • Redness and swelling around a wound
  • Sores that keep cropping up in the same place
  • Persistent, unexplained fever (temperature higher than 100.4 degrees Fahrenheit (38 degrees Celsius) 
  • A foul-smelling wound
  • Striking discoloration of the skin, with shades of greenish-black, blue, red, or bronze
  • Pus or discharge from a wound
  • Blisters and a crackling sound under the skin
  • Confusion, pain, fever, and low blood pressure, especially if the gangrene is internal
  • Shock

The earlier gangrene is treated, the more successful the treatment is likely to be. So if you have any of the above symptoms, seek immediate medical attention.

How is gangrene diagnosed?

If you have symptoms of gangrene, your medical team will perform a physical exam to check for signs of tissue death. They may also ask you about any chronic health conditions you have that could be related to the gangrene.

Your health care provider may also want to do lab tests to check for gangrene. A higher than normal amount of white blood cells, for example, can mean you have an infection. Your health care provider may take samples of tissue or fluid from the affected area and look at in the lab. If your health care provider suspects internal gangrene, he or she may order imaging tests or surgery to find out for sure.

How is gangrene treated?

Specific treatment for gangrene will be determined by your health care provider based on the following:

  • The extent of the problem
  • Your age, overall health, and medical history
  • Your tolerance for specific medications, procedures, or therapies
  • Expectations for the course of the disorder
  • The opinion of the health care providers involved in your care
  • Your opinion and preference

Treatment of gangrene will usually consist of one or more of these procedures:

  • Antibiotics. These medications can be used to kill bacteria in the affected area.
  • Surgery to remove the dead tissue. This is called debridement. It can help keep the gangrene from spreading to healthy tissues nearby. In cases where the gangrene is widespread, a finger, toe, or even a limb may need to be amputated.
  • Maggot debridement. This is a nonsurgical alternative to traditional debridement. During this procedure, clean fly larvae are placed on the affected area to eat away dead tissue and remove bacteria. This is a painless procedure.
  • Hyperbaric oxygen therapy. During this procedure, you are placed in a special pressurized chamber that administers oxygen at high pressures, forcing more oxygen into the affected area. This can speed healing and help kill bacteria. This treatment is especially effective in people who develop gangrene from diabetic foot ulcers.
  • Vascular surgery. If your gangrene is caused by poor blood flow, your health care provider may recommend surgery to improve circulation. People whose gangrene is a result of a blocked artery, for example, may have bypass surgery or an angioplasty to fix the problem.

What are the complications of gangrene?

Because gangrene can spread rapidly over a large area of the body, the amount of dead tissue can be quite large. Treating these large areas may result in:

  • Large areas of scarring
  • The need for reconstructive surgery
  • Amputation

Severe cases of gangrene may lead to organ failure and even death.

Can gangrene be prevented?

You can help prevent gangrene by carefully watching any wounds you have and getting immediate attention if signs of infection develop. In addition, people with certain conditions that can affect blood circulation (such as diabetes, peripheral vascular disease, Reynaud’s disease), should follow their health care provider’s instructions on managing their condition very carefully.

When should I call my health care provider?

Gangrene is a medical emergency. The outlook with gangrene depends on the location and size of the affected area, as well as any other medical conditions you might have. Gangrene is often life-threatening, so immediate medical attention is crucial. 

Key points

  • Gangrene is a dangerous and potentially fatal condition that happens when the blood flow to a large group of tissues is cut off.
  • People with diabetes, peripheral artery disease, and Raynaud’s disease are at higher risk for gangrene.
  • Symptoms of gangrene include coldness, numbness, pain, redness, or swelling in the affected area.
  • Gangrene is a medical emergency.


Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.