The exact cause likely differs for each type of neuropathy. Researchers think that over time, uncontrolled high blood sugar damages nerves and interferes with their ability to send signals, leading to diabetic neuropathy. High blood sugar also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.
However, a combination of factors may lead to nerve damage, including:
- Inflammation in the nerves caused by an autoimmune response. The immune system mistakes nerves as foreign and attacks them.
- Genetic factors unrelated to diabetes may make some people more likely to develop nerve damage.
- Smoking and alcohol abuse damage both nerves and blood vessels and significantly increase the risk of infection.