Diabetes is a serious illness, and failure to monitor and treat it can lead to difficult complications. One potential complication is gangrene, the death and decomposition of tissue in a part of the body, a cause of many diabetes-related amputations.

There are three primary causes of gangrene in people with diabetes:

  1. Damage to blood vessels. Individuals who have diabetes do not produce enough insulin, or are resistant to insulin, the hormone that helps cells absorb blood sugar. High blood sugar levels can damage blood vessels, interrupting the flow of blood to the extremities where gangrene is most likely to occur. This lack of blood flow also reduces the number of white blood cells to the area, making it more difficult to fight infections.

  2. Trauma to tissue. High levels of blood glucose may damage nerves, so people with diabetes may injure their skin (especially on the feet) without experiencing pain. Unaware they are hurt, they fail to get treatment for the wound.

  3. Bacterial infections. Untreated or prolonged wounds increase the risk of developing infections, which can lead to gangrene.

Obesity is also a risk factor for gangrene and often accompanies type 2 diabetes. Blood vessel disease, a suppressed immune system, and surgery may also raise the risk of gangrene.

Symptoms of Gangrene

There are several types of gangrene, but people with diabetes are most likely to develop wet gangrene, which is caused by a bacterial infection. Gangrene tissue appears swollen, blistering, and wet. It can also produce a foul odor. The main clinical sign of gangrene is a change in skin color to dark green or black. Wet gangrene spreads quickly and can be fatal.

Gangrene is most common in toes, fingers, and limbs, although it can also occur in muscles and internal organs.

The good news is that lower extremity amputations due to diabetes decreased 65 percent between 1996 and 2008 in the general diabetes population, according to the Centers for Disease Control (CDC). The decline is attributed to better diabetes management. However, the CDC reports that the rate is still about eight times higher among people with diagnosed diabetes compared to those without it.

If you have diabetes, it's important to check your feet regularly for wounds you might not feel due to nerve damage. Have a qualified diabetes or foot health care professional examine your feet annually. If you do develop a wound, see your physician promptly.  If your podiatrist asks you to wear a boot or stay off your foot, following his advice. It may help prevent amputation.

Amber Taylor, MD, reviewed this article.


"Gangrene," National Library of Medicine, last reviewed: August 24, 2011, accessed January 9, 2014. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004484/

"Gangrene," Mayo Clinic, August 10, 2011, accessed January 9, 2014. http://www.mayoclinic.org/diseases-conditions/gangrene/basics/definition/CON-20031120?p=1&DSECTION=causes

"Main Causes of Gangrene in Diabetes," DiabetesTreatmentGuide.org., accessed January 9, 2014. http://www.diabetestreatmentguide.org/main-causes-of-gangrene-in-diabetes/

"Gangrene," National Library of Medicine, August 24, 2011, accessed January 9, 2014. http://www.nlm.nih.gov/medlineplus/ency/article/007218.htm

"CDC report finds large decline in lower-limb amputations among U.S. adults with diagnosed diabetes," Centers for Disease Control, press release, January 24, 2012, accessed January 9, 2014. http://www.cdc.gov/media/releases/2012/p0124_lower_limb.html