Diabetic neuropathy is a chronic, pathological complication associated with diabetes mellitus, where nerve damage is incurred due to microvascular injury involving small blood vessels that supply nerves, resulting in peripheral sensory and motor and/or autonomic nerve dysfunction. Although commonly affecting distal and smaller nerves, infarction of proximal large nerves can also occur.

There may be a distal, often symmetric, polyneuropathy, or there may be focal or multifocal neuropathies. Symptoms typically include numbness, tingling, and/or burning pain in the extremities. Autonomic nerve dysfunction may occur and cause constipation, erectile dysfunction, dizziness, and urinary incontinence. If motor nerves are affected, patients may develop weakness. Symptoms usually progress. Diagnosis can be suspected in diabetic patients with classic symptoms, particularly those with poor glucose control.

Diabetic neuropathy usually develops after years of the disease and progresses slowly (years). Rapid progression is unusual.