Causes

Peripheral neuropathy is nerve damage caused by a number of different conditions. Health conditions that can cause peripheral neuropathy include:

• Autoimmune diseases. These include Sjogren's syndrome, lupus, rheumatoid arthritis, Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy and vasculitis.
• Diabetes. This is the most common cause. Among people with diabetes, more than halfwill develop some type of neuropathy.
• Infections. These include certain viral or bacterial infections, including Lyme disease, shingles, Epstein-Barr virus, hepatitis B and C, leprosy, diphtheria, and HIV.
• Inherited disorders. Disorders such as Charcot-Marie-Tooth disease are hereditary types of neuropathy.
• Tumors. Growths, cancerous (malignant) and noncancerous (benign), can develop on the nerves or press on nerves. Also, polyneuropathy can arise as a result of some cancers related to the body's immune response. These are a form of a degenerative disorder called paraneoplastic syndrome.
• Bone marrow disorders. These include an abnormal protein in the blood (monoclonal gammopathies), a form of bone cancer (myeloma), lymphoma and the rare disease amyloidosis.
• Other diseases. These include kidney disease, liver disease, connective tissue disorders and an underactive thyroid (hypothyroidism).

Other causes of neuropathies include:

• Alcoholism. Poor dietary choices made by people with alcoholism can lead to vitamin deficiencies.
• Exposure to poisons. Toxic substances include industrial chemicals and heavy metals such as lead and mercury.
• Medications. Certain medications, especially those used to treat cancer (chemotherapy), can cause peripheral neuropathy.
• Injury or pressure on the nerve. Injuries, such as from motor vehicle accidents, falls or sports injuries, can sever or damage peripheral nerves. Nerve pressure can result from having a cast or using crutches or repeating a motion such as typing many times.
• Vitamin deficiencies. B vitamins — including B-1, B-6 and B-12 — vitamin E and niacin are crucial to nerve health.

In a number of cases, no cause can be identified (idiopathic).