Topic Overview

Peripheral neuropathy is the most common type of diabetic neuropathy. It occurs when diabetes damages sensory nerves, which allow the brain to respond to sensations like pain, touch, temperature, and vibration. Peripheral neuropathy may also damage the motor nerves, which work with the muscles to control movement.

The effects and symptoms of peripheral neuropathy develop slowly over months or years. The first symptom is usually a slight burning sensation in the affected area. If blood sugar levels remain high over several years, the burning sensation greatly increases and then slowly goes away. It is replaced by a complete lack of feeling and sensation, or numbness, making the person more likely to injure the affected area.

Although peripheral neuropathy can develop almost anywhere in the body, it most often affects the feet and legs. Loss of the protective sensation—the reduced ability to feel pain—in the feet may lead to the formation of calluses and blisters, bone and joint problems, infection, and foot ulcers. For instance, small, repetitive injuries to the foot, such as those caused by a poorly fitting shoe, may lead to bigger problems simply because the person is unaware of them. Reduced feeling in the feet can also alter a person's step, leading to bone or joint problems.

If untreated, foot problems can become so severe that the foot or lower leg may have to be amputated. About 6 out of every 1,000 people with diabetes have an amputation.