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. It can also occur in the muscles and in organs inside the body, such as the gallbladder.
A condition that can damage the blood vessels and affect blood flow, such as diabetes or hardened arteries (atherosclerosis), increases the risk of gangrene.
Treatments for gangrene may include antibiotics, oxygen therapy, and surgery to restore blood flow and remove dead tissue. The earlier gangrene is identified and treated, the better the chances for recovery.
When gangrene affects the skin, signs and symptoms may include:
- Changes in skin color — ranging from pale gray to blue, purple, black, bronze or red
- 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 gangrene 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 the body, a condition called 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 98.6 F (37 C)
- Rapid heart rate
- Shortness of breath
When to see a doctor
Gangrene is a serious condition and needs emergency treatment. Call your health care provider immediately 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 of gangrene include:
- Lack of blood supply. The blood provides oxygen and nutrients to the body. It also provides the immune system with antibodies to fight infections. Without a proper blood supply, cells can't survive, and tissue dies.
- 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 bacteria have infected the 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. The surface of your skin may look normal at first.
As the condition worsens, the skin may become pale and then turn other colors such as gray or purplish red. The skin may look bubbly. It may make a crackling sound when you press on it because of the gas within the tissue.
Gas gangrene is most commonly caused by bacteria 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. Internal gangrene affects one or more of the organs, such as the intestines, gallbladder or appendix. It occurs when blood flow to an internal organ is blocked. For example, it may happen if the intestines bulge through a weakened area of muscle in the stomach area (hernia) and become twisted. Left untreated, internal gangrene can be deadly.
- Fournier's gangrene. This type of gangrene involves the genital organs. It usually affects men, but women also can get it. An infection in the genital area or urinary tract causes this type of gangrene.
- Meleney's gangrene. This is a rare type of gangrene. It's usually a complication of surgery. Painful skin lesions typically occur one to two weeks after a surgery. Another name for this condition is progressive bacterial synergistic gangrene.
Things that can increase the risk of gangrene include:
- Diabetes. High blood sugar levels can eventually damage blood vessels. Blood vessel damage can slow or block blood flow to a part of the body.
- Blood vessel disease. Hardened and narrowed arteries (atherosclerosis) and blood clots can block blood flow to an area of the body.
- Severe injury or surgery. Any process that causes trauma to the skin and underlying tissue, including frostbite, increases the risk of gangrene. The risk is greater 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. Extra weight can push on arteries, slowing blood flow and increasing the risk of infection and poor wound healing.
- Immunosuppression. Chemotherapy, radiation and certain infections, such as human immunodeficiency virus (HIV), can affect the body's ability to fight off infections.
- Injections. Rarely, injectable drugs have been linked to infection with bacteria that cause gangrene.
- Complications of coronavirus disease 2019 (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 link.
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.
Here are a few ways to help reduce the risk of developing gangrene:
- Manage diabetes. If you have diabetes, it's important to control your blood sugar levels. Also make sure you examine your hands and feet daily for cuts, sores and signs of infection, such as redness, swelling or drainage. Ask your health care provider to check your hands and feet at least once a year.
- Lose weight. Extra pounds raise the risk of diabetes. The weight also puts pressure on the arteries, slowing blood flow. Decreased blood flow increases infection risk and causes slow wound healing.
- Don't smoke or use tobacco. Long-term of tobacco damages the blood vessels.
- Wash your hands. Practice good hygiene. Wash any open wounds with a mild soap and water. Keep the hands clean and dry until they heal.
- Check for frostbite. Frostbite reduces blood flow in the affected body area. If you have skin that's pale, hard, cold and numb after being in cold temperatures, call your care provider.