Peripheral neuropathy is a type of nerve damage that typically affects the feet and legs and sometimes affects the hands and arms.

This type of neuropathy is very common. Up to one-half of people with diabetes have peripheral neuropathy.

Peripheral neuropathy refers to the many conditions that involve damage to the peripheral nervous system, which is a vast communications network that sends signals between the central nervous system (the brain and spinal cord) and all other parts of the body.

Peripheral nerves send many types of sensory information to the central nervous system (CNS), such as the message that your feet are cold. They also carry signals from the CNS to the rest of the body. Best known are the signals to the muscles that tell them to contract, which is how we move, but there are different types of signals that help control everything from our heart and blood vessels, digestion, urination and sexual function to our bones and immune system.

More than 20 million people in the U.S. are estimated to have some form of peripheral neuropathy, but this figure may be significantly higher as not all people with symptoms of neuropathy are tested for the disease and tests currently do not look for all forms of neuropathy.

Nerve signal interruption

The peripheral nerves are like cables that connect different parts of a computer or connect to the Internet. When they malfunction, complex functions can grind to a halt.

Nerve signaling in neuropathy is disrupted in three ways:

1. Loss of signals normally sent
2. Inappropriate signaling when there shouldn't be any 
3. Errors that distort the messages being sent

Some forms of neuropathy involve damage to only one nerve (mononeuropathy). Neuropathy affecting two or more nerves in different areas is called multiple mononeuropathy or mononeuropathy multiplex. More often, many or most of the nerves are affected (polyneuropathy).

Over time, high blood glucose, also called blood sugar, and high levels of fats, such as triglycerides, in the blood from diabetes can damage your nerves and the small blood vessels that nourish your nerves, leading to peripheral neuropathy.

If you have peripheral neuropathy, your feet, legs, hands, or arms may feel

• burning
• tingling, like “pins and needles”
• numb
• painful
• weak

You may feel extreme pain in your feet, legs, hands, and arms, even when they are touched lightly. You may also have problems sensing pain or temperature in these parts of your body.

Symptoms are often worse at night. Most of the time, you will have symptoms on both sides of your body. However, you may have symptoms only on one side.

If you have peripheral neuropathy, you might experience:

• changes in the way you walk
• loss of balance, which could make you fall more often
• loss of muscle tone in your hands and feet
• pain when you walk
• problems sensing movement or position
• swollen feet

Peripheral neuropathy can cause foot problems that lead to blisters and sores. If peripheral neuropathy causes you to lose feeling in your feet, you may not notice pressure or injuries that lead to blisters and sores. Diabetes can make these wounds difficult to heal and increase the chance of infections. These sores and infections can lead to the loss of a toe, foot, or part of your leg. Finding and treating foot problems early can lower the chances that you will develop serious infections.

This type of diabetes-related nerve damage can also cause changes to the shape of your feet and toes. A rare condition that can occur in some people with diabetes is Charcot’s foot, a problem in which the bones and tissue in your foot are damaged.

Peripheral neuropathy can make you more likely to lose your balance and fall, which can increase your chance of fractures and other injuries. The chronic pain of peripheral neuropathy can also lead to grief, anxiety, and depression.

Doctors diagnose peripheral neuropathy based on your symptoms, family and medical history, a physical exam, and tests. A physical exam will include a neurological exam and a foot exam.

Examination for neuropathy

If you have diabetes, you should get a thorough exam to test how you feel in your feet and legs at least once a year. During this exam, your doctor will look at your feet for signs of problems and check the blood flow and feeling, or sensation, in your feet by

• placing a tuning fork against your great toes and higher on your feet to check whether you can feel vibration
• touching each foot and some toes with a nylon strand to see if you can feel it—a procedure called a monofilament test
• reviewing your gait, or the patterns you make when you walk
• testing your balance

Your doctor may also check if you can feel temperature changes in your feet.

Your doctor may perform tests to rule out other causes of nerve damage, such as a blood test to check for thyroid problems, kidney disease, or low vitamin B12 levels. If low B12 levels are found, your doctor will do additional tests to determine the cause. Metformin use is among several causes of low vitamin B12 levels. If B12 deficiency is due to metformin, metformin can be continued with B12 supplementation.

You can prevent the problems caused by peripheral neuropathy by managing your diabetes, which means managing your blood glucose, blood pressure, and cholesterol. Staying close to your goal numbers can keep nerve damage from getting worse.

If you have diabetes, check your feet for problems every day and take good care of your feet. If you notice any foot problems, call or see your doctor right away.

Remove your socks and shoes in the exam room to remind your doctor to check your feet at every office visit. See your doctor for a foot exam at least once a year—more often if you have foot problems. Your doctor may send you to a podiatrist.

Doctors may prescribe medicine and other treatments for pain.

Medicines for nerve pain

Your doctor may prescribe medicines to help with pain, such as certain types of

• antidepressants, including
  • tricyclic antidepressants, such as nortriptyline, desipramine, imipramine, and amitriptyline
  • other types of antidepressants, such as duloxetine, venlafaxine, paroxetine, and citalopram
• anticonvulsants—medicines designed to treat seizures—such as gabapentin and pregabalin
• skin creams, patches, or sprays, such as lidocaine

Although these medicines can help with the pain, they do not change the nerve damage. Therefore, if there is no improvement with a medicine to treat pain, there is no benefit to continuing to take it and another medication may be tried.

All medicines have side effects. Ask your doctor about the side effects of any medicines you take. Doctors don’t recommend some medicines for older adults or for people with other health problems, such as heart disease.

Some doctors recommend avoiding over-the-counter pain medicines, such as acetaminophen and ibuprofen. These medicines may not work well for treating most nerve pain and can have side effects.

Other treatments for nerve pain

Your doctor may recommend other treatments for pain, including

• physical therapy to improve your strength and balance
• a bed cradle, a device that keeps sheets and blankets off your legs and feet while you sleep

Diabetes experts have not made special recommendations about supplements for people with diabetes. For safety reasons, talk with your doctor before using supplements or any complementary or alternative medicines or medical practices.