Causes and Risks of Gangrene in Diabetes Patients

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Gangrene is a condition that involves the death and decay of tissue caused by a loss of its blood supply or by a bacterial infection. It is usually treated by removing the dead tissue, often by amputation, as well as with antibiotics.


There are three different types of gangrene: dry, wet or gas gangrene. Of these, people with diabetes are at higher risk of having dry gangrene and wet gangrene because they have damage to their blood vessels from high blood sugar and they may have impaired ability to fight infection.

Toes, feet, lower limbs, hands and sometimes fingers can all become vulnerable to the conditions that may cause gangrene. Symptoms include numbness in the affected part and it may also be cold to the touch. Discoloration from red to blue or black may be seen and there may be a foul-smelling discharge.

Dry Gangrene

Dry gangrene is the result of loss of blood supply to the affected tissues, which then die and decay. Reduced blood flow or lack of circulation resulting from diabetes, cardiovascular problems, and smoking are the most common causes. High blood sugar over time damages the blood vessels, which increases the risk of developing dry gangrene if you have diabetes.

As the blood flow is choked off, tissues begin to die. It may develop slowly. At first, the area may become reddened but it gradually progresses to a brownish color. The skin may appear waxy. In the final stage, the affected body part will look withered and black in color.

Wet Gangrene

Bacterial infections can lead to wet gangrene as the germs invade the tissues. In people with diabetes, wet gangrene can develop at the site of foot ulcers.

You may have an impaired immune system with diabetes and this makes it more of a threat as you are more likely to be unable to fight off an infection in your feet or other tissues.

As the infection causes swelling, it can cut off blood circulation and this leads to the tissues dying. It can progress rapidly and there is a risk of developing septic shock, which can be deadly.

Gas Gangrene

This type of gangrene is most often caused by the Clostridium perfringens bacteria, which produces gas and toxins. It can cause gangrene anywhere in the body, sometimes deep in the organs. Gas gangrene can develop after surgery or trauma.

Risk factors for gas gangrene include diabetes, atherosclerosis, and colon cancer. It can develop suddenly and progress swiftly. This condition often requires emergency action to prevent shock, kidney failure, coma, and death. 


Gangrene is treatable if the symptoms are recognized early before the death of tissue occurs. After tissue dies, the usual treatment involves removal of the dead tissue or amputation of the affected body part, along with antibiotics. This is why many people with diabetes have amputations of their toes, feet, and lower legs. Hyperbaric oxygen treatment may also be used. Gangrene can require swift emergency treatment to save a limb or perform a life-saving amputation.

View Article Sources
  • Gas gangrene, MedlinePlus, U.S. National Library of Medicine.
  • Gangrene, MedlinePlus, U.S. National Library of Medicine.
  • Gangrene, Mayo Clinic Staff, Mayo Clinic.