Gangrene can develop when the supply of blood to an area of your body is interrupted.
This can occur as the result of an injury, an infection, or an underlying condition that affects your circulation.
There are several different types of gangrene, each with a different cause. The main types are:
People most at risk of gangrene are those with an underlying health condition that can affect the blood vessels and arteries (particularly if it's poorly managed), and those with a weakened immune system.
Conditions that can affect the blood vessels and increase your risk of developing gangrene include:
As blood vessels are naturally narrow, any damage or extra narrowing has the potential to block blood flow to a part of the body and cause gangrene.
People with diabetes have an increased risk of developing gangrene. This is because the high blood sugar levels associated with the condition can damage your nerves, particularly those in your feet, which can make it easy to injure yourself without realising.
High blood sugar can also damage your blood vessels, restricting the blood supply to your feet. Less blood means your feet will also receive fewer infection-fighting cells, so wounds will take longer to heal and are more likely to become infected.
It's therefore important that you take extra care of your feet if you have diabetes. Read more about foot care in preventing gangrene.
You're also at an increased risk of developing gangrene if you experience a traumatic injury or serious damage to your skin and tissues, such as:
These injuries can cause a sudden loss of blood to an area of your body, and any open wounds can become infected with bacteria.
Gangrene can also occur as a result of an infection that develops during surgery. However, with advances in surgical techniques and infection control, the chances of gangrene developing during surgery are small nowadays.
If your immune system is seriously weakened, minor infections can become more serious and can lead to gangrene. A weak immune system can be caused by:
However, for reasons that are unclear, gangrene can sometimes occur in young and otherwise healthy people.