Medically Reviewed by Shruthi N on May 27, 2024
5 min read

Gangrene happens when tissues in your body die after a loss of blood flow caused by illness, injury, or infection. It usually happens in extremities such as fingers, toes, and limbs, but it can also affect your organs and muscles. There are different types of gangrene, and all of them need medical care right away.

Gangrene vs. necrosis

Necrosis is a general term for cell death anywhere in your body. Gangrene is a type of necrosis that happens when you lose blood flow to a part of your body and the tissues in that area die.

There are two main causes of gangrene:

Lack of blood supply. This is the most common cause. Blood delivers oxygen and nutrients to tissues and without it, cells can't survive. Conditions that can affect blood flow include diabetes, peripheral artery disease, atherosclerosis (hardening of the arteries), and blood clots.

Infection. An untreated bacterial infection can cause gangrene. When bacteria invade your tissues and multiply, they can damage blood vessels and cut off blood flow to the area.

If you have any condition that decreases your blood flow, you have a higher risk of getting gangrene.

Diabetes. High blood sugar levels damage your blood vessels over time. This can slow blood flow to areas of your body.

Atherosclerosis. This is a condition in which your blood vessels harden and become narrow, which slows down blood flow.

Peripheral artery disease. A buildup of fats in your arteries can block blood flow to your legs.

Obesity. Extra body weight can put pressure on your blood vessels and block blood flow.

Other factors that can cause gangrene are:

  • A weakened immune system due to cancer treatment or certain infections such as HIV/AIDS
  • Smoking, as it affects blood flow throughout the body
  • Trauma or serious injury, which can increase your risk of infection
  • Serious frostbite, which can cut off blood flow

There are several types of gangrene:

Dry gangrene: This is more common in people who have vascular disease, diabetes, and autoimmune diseases. It usually affects your hands and feet. It happens when something such as poor circulation blocks blood flow to a certain area. As your tissue dries up, it changes color. It may be brown to purplish-blue to black. The tissue often falls off.

Wet gangrene: This type involves an infection. It’s called "wet" because it causes pus. Infection from wet gangrene can spread swiftly around your body.

Internal gangrene: This type affects your internal organs. It’s usually related to an infected organ such as your appendix or colon.

Gas gangrene: Gas gangrene is rare but especially dangerous. It happens when you get an infection deep inside your body, such as inside muscles or organs, usually because of trauma. Bacteria called clostridia release dangerous toxins or poisons, along with gas that can be trapped in your tissue. Your skin may become pale and gray and make a crackling sound when pressed. Without treatment, gas gangrene can be deadly within 48 hours.

Fournier’s gangrene: Also a rare condition, it is caused by an infection in your genital area. It affects men more often than women.

Meleney’s gangrene: This type causes painful lesions on your skin 1-2 weeks after surgery or minor trauma. It’s also rare.

Gangrene symptoms depend on where it happens and what causes it. 

With dry gangrene, the most common symptoms are tissue that gradually turns dry and black. It often starts with a red line surrounding the dying tissue.

With wet gangrene, pus, redness, and swelling are common symptoms. 

Other symptoms can include:

  • Cold, numb skin
  • Pain
  • Fever and feeling unwell
  • A crackling noise when you press on the affected area
  • Thin, shiny, or hairless skin

Internal gangrene causes severe pain in the affected area. For example, if you have gangrene in your appendix or colon, you’ll probably have belly pain. Internal gangrene can also cause a fever, and in such cases, it requires emergency surgery.

Your doctor will ask about your symptoms and medical history. You may have:

Blood tests. These look for bacteria or check for signs of infection, such as more white blood cells than usual.

Imaging tests. CT and MRI tests tell your doctor whether your gangrene has spread and if gas has built up in your tissues. In an arteriogram, your doctor injects dye into your blood and then takes an X-ray to check blood flow and look for blocked arteries.

Cultures. Your doctor might take a sample of blood, fluid, or tissue, and look at it under a microscope for signs of bacteria or tissue death.

Surgery. This can confirm internal gangrene or tell your doctor whether gangrene has spread.

Gangrene can quickly spread to other areas of the body if left untreated. You may need to have a limb amputated or removed and have reconstructive surgery. It can also cause a lot of scarring. If the condition gets very severe, it can cause your organs to fail and lead to death.

If an infection gets into your blood, you may get sepsis and go into septic shock. This needs treatment right away. Symptoms include:

  • Low blood pressure
  • Rapid heartbeat
  • Shortness of breath
  • Change in body temperature
  • Lightheadedness
  • Confusion

Treatment for all forms of gangrene involves removing dead tissue, treating and stopping the spread of infection, and treating the condition that caused the gangrene. The sooner you get treatment, the more likely you are to recover.

Your treatment depends on the type of gangrene and may include:

Medication. Antibiotics treat a bacterial infection, and pain medications can help ease discomfort.

Debridement. This surgery is done to remove dead tissue and keep the infection from spreading. 

Amputation. They may need to remove an affected limb, finger, or toe.

Blood vessel repair. They can also repair damaged blood vessels to improve blood flow.

Skin grafting. If you need reconstruction, your doctor might be able to take healthy tissue from another area of your body.

Hyperbaric oxygen therapy. This involves spending time in a special chamber filled with oxygen at a higher pressure than oxygen found in the outside air. This can help your blood carry more oxygen and speed tissue healing. Oxygen therapy can also slow the growth of bacteria.

The best ways to prevent gangrene are to:

Manage your health conditions. If you have diabetes, keep your blood sugar levels under control. Check your hands, feet, and legs regularly for signs of injury, slow wound healing, or other skin problems. Follow your doctor’s advice on living with other conditions that affect your blood flow such as peripheral artery disease or Raynaud’s phenomenon.

Watch your wounds. Get medical care right away if you see signs of infection.

Don’t smoke. Tobacco can damage your blood vessels.

Keep a healthy weight. Extra pounds can put pressure on your arteries, blocking blood flow.

Stay warm. Frostbite blocks blood flow and can lead to gangrene.

Protect your feet if you have diabetes or peripheral vascular disease. This includes keeping your feet clean, always wearing well-fitting shoes when outside, and keeping your toenails trimmed.

Certain health conditions that affect blood flow or your immune system can increase your risk of gangrene. It's important to work with your doctor to manage your condition. If you think you have gangrene, it's important to seek medical attention right away to keep it from spreading.