A diabetic foot ulcer is caused by neuropathic (nerve) and vascular (blood vessel) complications of diabetes. Nerve damage due to diabetes causes altered or complete loss of feeling in the foot and/or leg. This is known as peripheral neuropathy.

Anyone who has diabetes can develop a foot ulcer. Native Americans, African Americans, Hispanics, and older men are more likely to develop ulcers. People who use insulin are at higher risk of developing a foot ulcer, as are patients with diabetes-related kidney, eye, and heart disease. Being overweight and using alcohol and tobacco also play a role in the development of foot ulcers.

Ulcers form due to a combination of factors, such as lack of feeling in the foot, poor circulation, foot deformities, irritation (such as friction or pressure), and trauma, as well as duration of diabetes. Patients who have diabetes for many years can develop neuropathy, a reduced or complete lack of ability to feel pain in the feet due to nerve damage caused by elevated blood glucose levels over time. The nerve damage often can occur without pain, and one may not even be aware of the problem. Your podiatrist can test feet for neuropathy with a simple, painless tool called a monofilament.

Vascular disease can complicate a foot ulcer, reducing the body’s ability to heal and increasing the risk for an infection. Elevations in blood glucose can reduce the body’s ability to fight off a potential infection and also slow healing.