Overview

Gangrene is death of body tissue due to a lack of blood flow or a serious bacterial infection. Gangrene commonly affects the arms and legs, including the toes and fingers, but it can also occur in the muscles and in organs inside the body, such as the gallbladder.

Your risk of gangrene is higher if you have an underlying condition that can damage your blood vessels and affect blood flow, such as diabetes or hardened arteries (atherosclerosis).

Treatments for gangrene include surgery to restore blood flow and remove dead tissue, antibiotics if there is an infection, and hyperbaric oxygen therapy. The earlier gangrene is identified and treated, the better your chances for recovery.

Symptoms

When gangrene affects your skin, signs and symptoms may include:

  • Skin discoloration — ranging from pale to blue, purple, black, bronze or red, depending on the type of gangrene you have
  • Swelling
  • Blisters
  • Sudden, severe pain followed by a feeling of numbness
  • A foul-smelling discharge leaking from a sore
  • Thin, shiny skin, or skin without hair
  • Skin that feels cool or cold to the touch

If you have a type of gangrene that affects tissues beneath the surface of your skin, such as gas gangrene or internal gangrene, you may also have a low-grade fever and generally feel unwell.

If the germs that caused the gangrene spread through your body, septic shock can occur. Signs and symptoms of septic shock include:

  • Low blood pressure
  • Fever, although some people may have a body temperature lower than the normal 98.6 F (37 C)
  • Rapid heart rate
  • Lightheadedness
  • Shortness of breath
  • Confusion

When to see a doctor

Gangrene is a serious condition and needs emergency treatment. Call your doctor right away if you have persistent, unexplained pain in any area of your body along with one or more of the following signs and symptoms:

  • Persistent fever
  • Skin changes — including discoloration, warmth, swelling, blisters or lesions — that won't go away
  • A foul-smelling discharge leaking from a sore
  • Sudden pain at the site of a recent surgery or trauma
  • Skin that's pale, hard, cold and numb

Causes

Causes of gangrene include:

  • Lack of blood supply. Your blood provides oxygen and nutrients to your body. It also provides your immune system with antibodies to ward off infections. Without a proper blood supply, your cells can't survive, and your tissue decays.
  • Infection. An untreated bacterial infection can cause gangrene.
  • Traumatic injury. Gunshot wounds or crushing injuries from car crashes can cause open wounds that let bacteria into the body. If the bacteria infect tissues and remain untreated, gangrene can occur.

Types of gangrene

  • Dry gangrene. This type of gangrene involves dry and shriveled skin that looks brown to purplish blue or black. Dry gangrene may develop slowly. It occurs most commonly in people who have diabetes or blood vessel disease, such as atherosclerosis.
  • Wet gangrene. Gangrene is referred to as wet if there's a bacterial infection in the affected tissue. Swelling, blistering and a wet appearance are common features of wet gangrene.

    Wet gangrene may develop after a severe burn, frostbite or injury. It often occurs in people with diabetes who unknowingly injure a toe or foot. Wet gangrene needs to be treated immediately because it spreads quickly and can be deadly.

  • Gas gangrene. Gas gangrene typically affects deep muscle tissue. If you have gas gangrene, the surface of your skin may look normal at first.

    As the condition worsens, your skin may become pale and then turn gray or purplish red. The skin may look bubbly and may make a crackling sound when you press on it because of the gas within the tissue.

    Gas gangrene is most commonly caused by infection with a bacterium called Clostridium perfringens. Bacteria gather in an injury or surgical wound that has no blood supply. The bacterial infection produces toxins that release gas and cause tissue death. Like wet gangrene, gas gangrene is a life-threatening condition.

  • Internal gangrene. Gangrene that affects one or more of your organs, such as your intestines, gallbladder or appendix, is called internal gangrene. This type of gangrene occurs when blood flow to an internal organ is blocked — for example, when your intestines bulge through a weakened area of muscle in your stomach area (hernia) and become twisted.

    Left untreated, internal gangrene can be deadly.

  • Fournier's gangrene. Fournier's gangrene involves the genital organs. Men are more often affected, but women also can develop this type of gangrene. An infection in the genital area or urinary tract causes this type of gangrene.
  • Meleney's gangrene. This rare type of gangrene — also called progressive bacterial synergistic gangrene — is usually a complication of surgery. People with Meleney's gangrene develop painful skin lesions one to two weeks after their operations.

Risk factors

Several factors increase your risk of developing gangrene. These include:

  • Diabetes. If you have diabetes, your body doesn't produce enough of the hormone insulin (which helps your cells take up blood sugar) or is resistant to the effects of insulin. High blood sugar levels can eventually damage blood vessels, decreasing or interrupting blood flow to a part of your body.
  • Blood vessel disease. Hardened and narrowed arteries (atherosclerosis) and blood clots also can block blood flow to an area of your body.
  • Severe injury or surgery. Any process that causes trauma to your skin and underlying tissue, including an injury or frostbite, increases your risk of developing gangrene, especially if you have an underlying condition that affects blood flow to the injured area.
  • Smoking. People who smoke have a higher risk of gangrene.
  • Obesity. Obesity often accompanies diabetes and vascular disease, but the stress of extra weight alone can also compress arteries, leading to reduced blood flow and increasing your risk of infection and poor wound healing.
  • Immunosuppression. If you have an infection with the human immunodeficiency virus (HIV) or if you're undergoing chemotherapy or radiation therapy, your body's ability to fight off an infection is impaired.
  • Medications or drugs that are injected. In rare instances, certain medications and illegal drugs that are injected have been shown to cause infection with bacteria that cause gangrene.
  • Complications of COVID-19. There have been a few reports of people getting dry gangrene in their fingers and toes after having COVID-19-related blood clotting problems (coagulopathy). More research is needed to confirm this association.

Complications

Gangrene can lead to serious complications if it's not immediately treated. Bacteria can spread quickly to other tissues and organs. You may need to have a body part removed (amputated) to save your life.

Removal of infected tissue can lead to scarring or the need for reconstructive surgery.

Prevention

Here are a few suggestions to help you reduce your risk of developing gangrene:

  • Care for your diabetes. If you have diabetes, make sure you examine your hands and feet daily for cuts, sores, and signs of infection, such as redness, swelling or drainage. Ask your doctor to examine your hands and feet at least once a year, and try to maintain control over your blood sugar levels.
  • Lose weight. Excess pounds not only put you at risk of diabetes but also place pressure on your arteries, constricting blood flow and putting you at risk of infection and slow wound healing.
  • Don't use tobacco. The chronic use of tobacco products can damage your blood vessels.
  • Help prevent infections. Wash any open wounds with a mild soap and water and try to keep them clean and dry until they heal.
  • Watch out when the temperature drops. Frostbitten skin can lead to gangrene because frostbite reduces blood circulation in an affected area. If you notice that any area of your skin has become pale, hard, cold and numb after prolonged exposure to cold temperatures, call your doctor.