Nerve damage, known medically as peripheral neuropathy, affects about 2.4% of the general population and over 8% of people older than 55. The causes range from chronic diseases and nutritional gaps to physical injuries and toxic exposures. Diabetes is the single most common cause, but dozens of other conditions, medications, and lifestyle factors can also damage the nerves in your hands, feet, and throughout your body.
Diabetes and High Blood Sugar
Persistently elevated blood sugar is the leading cause of nerve damage worldwide. Over time, excess glucose in the bloodstream triggers a chain of events that slowly destroys nerve fibers, particularly in the feet and legs. The damage happens through several overlapping pathways.
First, high blood sugar reduces the ability of tiny blood vessels to deliver oxygen to nerves. It is not that blood volume drops, but that the vessel walls become less permeable, essentially starving the nerve of oxygen. Second, glucose gets converted into sugar alcohols like sorbitol and fructose through a process called the polyol pathway. These byproducts accumulate inside the protective cells that wrap around nerve fibers, causing oxidative stress that breaks down the nerve’s support structure. Third, when proteins and fats are exposed to high glucose for long periods, they form highly reactive molecules called advanced glycation end products. These molecules trigger inflammation that further damages nerve tissue.
The result is a gradual loss of sensation that typically starts in the toes and feet and moves upward. Because the damage develops slowly, many people with diabetes have significant nerve injury before they notice symptoms.
Vitamin and Nutrient Deficiencies
Your nerves depend on specific nutrients to maintain their protective coating and transmit signals properly. The deficiencies most likely to cause nerve damage involve vitamins B1, B6, B9 (folate), B12, vitamin E, and the mineral copper. Even a relatively mild B12 deficiency can affect the nervous system and brain function, which is notable because B12 deficiency is common in older adults and people who take certain acid-reducing medications.
Interestingly, too much vitamin B6 can also cause neuropathy. People who take high-dose B6 supplements over long periods sometimes develop tingling and numbness in their hands and feet, the very symptoms they might be trying to prevent. This makes B6 one of the few vitamins where both deficiency and excess are toxic to nerves.
Autoimmune Diseases
In autoimmune neuropathy, the immune system mistakenly attacks the body’s own nerve tissue. Several conditions are known to do this. Guillain-Barré syndrome causes rapid-onset weakness and numbness when the immune system attacks the nerve’s protective myelin sheath, sometimes after an infection. Chronic inflammatory demyelinating polyneuropathy (CIDP) is a slower, longer-lasting version of this same process.
Lupus, rheumatoid arthritis, Sjögren’s syndrome, and vasculitis (inflammation of blood vessels) can all damage peripheral nerves as well. In these conditions, the nerve damage is sometimes a secondary effect of inflamed blood vessels cutting off the nerve’s blood supply, rather than a direct immune attack on the nerve itself. Some cancers tied to immune system dysfunction also produce antibodies that target peripheral nerves.
Physical Injury and Nerve Compression
Nerves can be damaged in an instant or worn down over months of repetitive pressure. Car accidents, falls, and sports injuries can sever or stretch peripheral nerves outright. But the more common scenario is gradual compression, where a nerve gets squeezed in a tight anatomical space.
Carpal tunnel syndrome is the classic example. The median nerve runs through a narrow channel in the wrist, and anything that reduces that space, a fracture, arthritis, fluid retention, or repetitive wrist flexion, can irritate the nerve and cause numbness, tingling, and weakness in the hand. Working with vibrating tools or on assembly lines that require repeated wrist movements increases the risk. Even poor posture can play a role: rolling the shoulders forward shortens neck and shoulder muscles, compressing nerves higher up in the chain.
Other common compression sites include the elbow (cubital tunnel syndrome, affecting the ulnar nerve) and the spine, where a herniated disc can press on nerve roots as they exit the spinal cord.
Alcohol Use
Chronic heavy drinking damages nerves through what appears to be a double hit. Alcohol itself is directly toxic to nerve fibers. At the same time, excessive alcohol use impairs the body’s ability to absorb and store key vitamins and minerals, particularly the B vitamins that nerves need to function. The combination of direct poisoning and nutritional depletion accelerates nerve fiber breakdown.
Alcoholic neuropathy typically causes burning or prickling sensations in the feet and legs, muscle weakness, and problems with balance. The damage can stabilize or partially improve if drinking stops and nutritional deficiencies are corrected, but nerves that have been severely damaged may not fully recover.
Medications and Toxic Exposures
Certain medications are well-known causes of nerve damage, with chemotherapy drugs being the most significant. Several classes of cancer drugs cause what is called chemotherapy-induced peripheral neuropathy, including taxanes, platinum-based drugs, vinca alkaloids, and others. Each of these drugs injures neurons in a slightly different way, but the end result is similar: numbness, pain, or weakness in the hands and feet that can persist long after treatment ends. This is one of the most common and debilitating side effects cancer survivors face.
Outside of medications, exposure to industrial chemicals and heavy metals like lead and mercury can poison peripheral nerves. Occupational exposure is the usual route, though environmental contamination is also a risk in some areas.
Infections
Several viral and bacterial infections can inflame or directly damage nerves. Shingles, caused by reactivation of the chickenpox virus, is one of the most recognizable. The virus lives in nerve tissue and, when it reactivates, causes intense pain along the path of the affected nerve. In some people, nerve pain persists for months or years after the rash clears, a condition called postherpetic neuralgia.
HIV can damage peripheral nerves both directly and through the medications used to treat it. Lyme disease, caused by a tick-borne bacterium, can lead to nerve inflammation if untreated. Hepatitis C, herpes simplex, and other infections also carry neuropathy risk. In Guillain-Barré syndrome, the nerve damage is technically autoimmune, but it is frequently triggered by a preceding bacterial or viral infection.
Inherited Conditions
Some people are genetically predisposed to nerve damage. Charcot-Marie-Tooth disease is the most common inherited peripheral nerve disorder, affecting roughly 1 in 3,300 people worldwide and an estimated 150,000 people in the United States. It encompasses a group of hereditary conditions that progressively damage the peripheral nerves in the feet, legs, and hands.
The disease comes in several forms. Type 1 involves abnormalities in myelin, the fatty insulation around nerve fibers, which slows nerve signal transmission. Type 2 affects the axon itself, the long fiber that carries the electrical impulse, reducing signal strength. Some intermediate forms involve both problems simultaneously. Symptoms typically appear in adolescence or early adulthood and worsen over time, leading to muscle wasting and loss of sensation in the extremities. The pattern of inheritance varies: some forms require only one copy of the mutated gene from one parent, while others require copies from both parents.
Other Medical Conditions
Several additional diseases contribute to nerve damage through indirect mechanisms. Kidney disease and liver disease allow toxins to build up in the bloodstream that would normally be filtered out, and those toxins can injure nerve fibers over time. Hypothyroidism, an underactive thyroid gland, causes fluid retention and tissue swelling that can compress nerves and impair their function.
In roughly 25% to 30% of neuropathy cases, no specific cause is ever identified. This is called idiopathic neuropathy, and it is more common in older adults. Even without a clear diagnosis, the symptoms and management approach remain similar to other forms of nerve damage.