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.