Peripheral neuropathy is damage to the nerves outside your brain and spinal cord, typically affecting your hands and feet first. About 2.4% of the global population has some form of peripheral nerve disorder, and that number climbs to 8% in older adults. The condition can cause pain, numbness, weakness, and a range of other symptoms depending on which nerves are involved.
How Peripheral Nerves Get Damaged
Your peripheral nerves carry signals between your brain, spinal cord, and the rest of your body. When these nerves are damaged, those signals get disrupted, distorted, or lost entirely. The damage generally happens in one of two ways.
In the first, the nerve fiber itself breaks down. A metabolic problem, such as chronically high blood sugar, disrupts the nerve cell’s ability to maintain its longest extensions. Because nerve fibers can stretch several feet from the spinal cord to the toes, the most distant portions deteriorate first. This is why symptoms almost always start in the feet and hands before moving inward.
In the second, the insulating layer around nerve fibers (called the myelin sheath) gets attacked. This layer works like the coating on an electrical wire: it speeds up signal transmission and protects the fiber underneath. When the immune system mistakenly targets this coating, or when a toxin disrupts the cells that produce it, nerve signals slow down dramatically or stop altogether. The result is weakness and loss of sensation, sometimes developing rapidly over days or weeks.
Types of Peripheral Neuropathy
Peripheral neuropathy is an umbrella term. The specific type depends on how many nerves are affected and where.
- Polyneuropathy is the most common form. It affects many nerves at once, usually symmetrically on both sides of the body. Diabetic neuropathy is a classic example.
- Mononeuropathy involves a single peripheral nerve trunk. Carpal tunnel syndrome, where the nerve at the wrist is compressed, is one familiar example.
- Mononeuritis multiplex is a less common, more serious pattern. It involves two or more individual nerve trunks in random, asymmetric locations throughout the body. It tends to be painful and often signals an underlying autoimmune or vascular condition.
What Causes It
Diabetes is the single most common cause. More than half of people with chronic type 1 or type 2 diabetes will develop some form of neuropathy over the course of their disease. Years of elevated blood sugar gradually starve and damage nerve fibers, particularly in the legs and feet.
But diabetes is far from the only trigger. Other well-established causes include:
- Vitamin deficiencies: Low levels of B1, B6, B12, vitamin E, or copper can directly harm nerve health. B12 deficiency is especially common in older adults and people taking certain acid-reducing medications.
- Autoimmune diseases: Conditions like lupus, rheumatoid arthritis, Sjögren’s syndrome, Guillain-Barré syndrome, and vasculitis can trigger the immune system to attack peripheral nerves or their insulating sheath.
- Alcohol use disorder: Heavy, prolonged alcohol use damages nerves both directly and through the nutritional deficiencies it causes.
- Infections: Shingles, Lyme disease, hepatitis B and C, HIV, and leprosy can all damage peripheral nerves.
- Toxin exposure: Industrial chemicals, heavy metals like lead and mercury, and certain chemotherapy drugs are known to cause nerve damage.
- Kidney or liver disease: These conditions allow waste products to accumulate in the blood, which can be toxic to nerves.
- Hypothyroidism: An underactive thyroid gland is an underrecognized but treatable cause.
- Physical injuries and repetitive stress: Fractures, falls, sports injuries, and repetitive motions like typing can compress or sever peripheral nerves.
- Inherited conditions: Charcot-Marie-Tooth disease is the most common hereditary neuropathy, passed through families.
In a significant number of cases, no cause is ever identified. This is called idiopathic peripheral neuropathy, and it’s more common than many people realize.
Symptoms by Nerve Type
Your peripheral nervous system contains three types of nerves, and the symptoms you experience depend on which type is damaged. Many people have a mix.
Sensory Nerve Damage
Sensory nerves carry information about touch, temperature, and pain. When they’re damaged, you may feel tingling, burning, or stabbing pain in your feet or hands, often worse at night. Some people describe the sensation as walking on pebbles or wearing invisible socks. Over time, the pain can give way to numbness, which is actually more dangerous because you lose the ability to feel injuries, blisters, or infections on your feet.
Motor Nerve Damage
Motor nerves control your muscles. Damage here causes weakness, muscle cramps, and twitching. You might notice difficulty gripping objects, buttoning shirts, or walking steadily. In advanced cases, muscles can visibly shrink from lack of nerve stimulation.
Autonomic Nerve Damage
Autonomic nerves control functions you don’t consciously think about, and damage to them produces some of the most varied and surprising symptoms. These include dizziness or lightheadedness when standing up (from blood pressure regulation problems), a resting heart rate that’s abnormally fast or slow, bloating, nausea, constipation, or diarrhea from slowed digestion, bladder problems including incontinence or difficulty emptying completely, excessive sweating or an inability to sweat normally, and sexual dysfunction in both men and women. Autonomic neuropathy can also prevent you from feeling the warning signs of dangerously low blood sugar if you have diabetes, and it can slow your pupils’ response to light, making nighttime driving more difficult.
How It’s Diagnosed
Diagnosis typically starts with a physical exam and a detailed history of your symptoms, medications, alcohol use, and family background. Blood tests often follow to check for diabetes, vitamin deficiencies, thyroid function, kidney and liver health, and markers of autoimmune disease.
The main specialized test is an electrodiagnostic study, which measures how quickly and strongly electrical signals travel through your nerves and how well your muscles respond. This test is effective at detecting damage to large nerve fibers, the ones responsible for muscle control and certain types of sensation. However, it cannot detect small fiber neuropathy, the type that causes burning pain, temperature sensitivity, and autonomic symptoms. If your symptoms are typical of neuropathy but the electrodiagnostic study comes back normal, a skin biopsy or autonomic reflex testing may be needed. The skin biopsy involves taking a tiny punch of skin (usually from the lower leg) and counting the small nerve fibers under a microscope.
Complications Worth Knowing About
The most serious complications tend to occur in people with diabetic neuropathy, and they center on the feet. When you can’t feel pain in your feet, small cuts, blisters, and pressure sores go unnoticed and untreated. Over half of diabetic foot ulcers become infected, and bacterial communities can form within the wound that resist both the immune system and antibiotics. Up to 50% of foot ulcers develop a bone infection. In the most severe cases, amputation becomes necessary, occurring in up to 30% of foot ulcer cases. People with diabetes face a 10- to 20-fold higher risk of lower limb amputation compared to the general population.
Another complication is Charcot neuroarthropathy, where repeated unnoticed injuries cause the bones in the foot to weaken, fracture, and collapse. The foot becomes red, hot, and swollen, and without treatment, it can develop a permanent “rocker-bottom” deformity that makes walking extremely difficult.
Treatment and Management
Treatment starts with addressing the underlying cause whenever possible. For diabetic neuropathy, tighter blood sugar control can slow progression and, in early stages, partially reverse nerve damage. Correcting a B12 deficiency, treating an underactive thyroid, stopping a toxic exposure, or managing an autoimmune condition can all halt further nerve damage and sometimes allow partial recovery.
For pain management, several classes of medication are used, but the response varies widely from person to person. Many people try more than one before finding adequate relief. Non-drug approaches also play a meaningful role. Transcutaneous electrical nerve stimulation (TENS), which uses mild electrical currents through pads placed on the skin, has shown effectiveness for painful diabetic neuropathy. Exercise programs that combine strength training, balance work, and aerobic activity can improve sensory function and reduce pain scores. Some research suggests that combining structured exercise with cognitive behavioral therapy enhances symptom management further.
Practical daily habits matter as much as formal treatment. Checking your feet daily for cuts or sores (using a mirror for the soles), wearing well-fitting shoes, keeping blood sugar within target ranges, and limiting alcohol all help protect vulnerable nerves. Weight loss through dietary changes and physical activity has been shown to both prevent and partially reverse the effects of diabetic neuropathy in some studies.