Neuropathy is damage to one or more nerves outside the brain and spinal cord, causing pain, numbness, weakness, or problems with automatic body functions like digestion and heart rate. It affects millions of people worldwide, with diabetes being the single most common cause. Roughly 36% of people with diabetes develop peripheral neuropathy, but the condition has dozens of other triggers ranging from vitamin deficiencies to chemotherapy.
Types of Neuropathy
Neuropathy is grouped by how many nerves are involved and where they are. A mononeuropathy affects a single nerve, like carpal tunnel syndrome compressing the nerve in your wrist. A multifocal neuropathy damages several individual nerves in different areas of the body. A polyneuropathy, the most common pattern, affects many nerves at once and typically starts in the longest nerves first, which is why symptoms usually begin in the feet and hands.
Beyond this structural classification, neuropathy is also described by which part of the nerve is damaged. In axonal neuropathy, the nerve fiber itself breaks down. In demyelinating neuropathy, the protective insulation around the nerve deteriorates, slowing signal transmission. Many cases involve a mix of both. This distinction matters because it changes the pace of the disease and how well nerves can recover.
Common Causes
Diabetes is responsible for more cases of neuropathy than any other single condition. Persistently high blood sugar damages small blood vessels that feed nerves, gradually starving them of oxygen and nutrients. But the list of other causes is long.
Alcohol use is one of the most common associations. Whether the damage comes from a direct toxic effect of alcohol on nerves, from the chronic malnutrition that often accompanies heavy drinking, or from both remains difficult to untangle. Thiamine (vitamin B1) deficiency is particularly common in people with alcohol use disorder and can cause its own serious neurological problems.
Vitamin B12 deficiency is another well-established cause. Strict vegans are at risk because B12 comes almost exclusively from animal products, but the more common culprits are conditions that block absorption: pernicious anemia, chronic acid-reducing medications, gastric bypass surgery, and Crohn’s disease affecting the end of the small intestine.
Chemotherapy drugs cause neuropathy in roughly 30% of patients who receive certain agents. Platinum-based drugs used in many cancer regimens damage nerves by binding to DNA inside nerve cells and triggering cell death. One drug in this class, oxaliplatin, also causes a distinctive temporary syndrome where cold temperatures trigger sharp pain in the hands and face, a result of the drug directly interfering with the nerve’s electrical signaling.
Other causes include autoimmune diseases (lupus, rheumatoid arthritis, Guillain-Barré syndrome), infections (HIV, shingles, Lyme disease), kidney disease, inherited conditions like Charcot-Marie-Tooth disease, and physical injuries that crush or compress nerves.
How Nerve Damage Happens
Healthy nerves transmit electrical signals efficiently because they’re wrapped in a fatty insulating layer called myelin. When this layer breaks down, the nerve has to work much harder to send signals. Sodium channels that are normally concentrated at small gaps in the insulation get redistributed across the bare nerve, flooding the fiber with sodium. The nerve’s energy pumps struggle to keep up, and eventually calcium builds up inside the fiber. That excess calcium activates destructive enzymes that break down the nerve’s internal scaffolding from within.
In axonal neuropathy, the nerve fiber itself degenerates. Without a healthy supply of energy from surrounding support cells, the fiber can’t maintain its structure or transport essential materials along its length. The result is the same either way: signals slow down, become distorted, or stop entirely.
Symptoms by Nerve Type
What neuropathy feels like depends entirely on which nerves are affected. Most people experience some combination of sensory, motor, and autonomic symptoms.
Sensory Nerve Damage
Sensory neuropathy is the most recognizable form. It typically starts in the toes and feet, then gradually moves upward. You might feel tingling, burning, or stabbing pain, or a sensation like wearing invisible gloves or socks. Over time, the nerves may stop sending signals altogether, leaving areas numb. This loss of protective sensation is dangerous because you can injure your foot without realizing it, allowing small wounds to become serious infections.
Motor Nerve Damage
When motor nerves are involved, muscles weaken and can eventually waste away. This may show up as difficulty gripping objects, tripping while walking, or muscle cramps and twitching. In severe cases, the muscles in the feet change shape, creating pressure points that increase the risk of skin breakdown.
Autonomic Nerve Damage
Autonomic neuropathy is the least visible but potentially the most disruptive. These nerves control functions your body handles automatically, so damage can affect nearly every organ system. Your heart rate may respond sluggishly to position changes, causing lightheadedness when you stand up. Your digestive system may slow down, leading to bloating, nausea, constipation, or unpredictable diarrhea. Bladder nerves can make it difficult to sense when you need to urinate, raising the risk of infections. Sweat glands may overwork in some areas and shut down in others. Sexual function is commonly affected: erectile dysfunction in men, and reduced sensation and lubrication in women. Some people lose the ability to feel the warning signs of dangerously low blood sugar, a condition called hypoglycemia unawareness.
How Neuropathy Is Diagnosed
Diagnosis usually starts with a physical exam and a detailed history of your symptoms. Your doctor will check reflexes, sensation (using tools like a tuning fork or thin nylon filament), and muscle strength. Blood tests can identify common underlying causes like diabetes, B12 deficiency, kidney disease, or inflammatory markers.
When more detail is needed, nerve conduction studies and electromyography (EMG) are the standard next steps. Nerve conduction studies measure how fast electrical signals travel through your nerves and how strong those signals are. Slowed conduction speed suggests the insulating myelin is damaged, while reduced signal strength points to damage in the nerve fibers themselves. EMG uses a thin needle inserted into a muscle to evaluate how well the nerve is communicating with that muscle. Together, these tests can confirm neuropathy, pinpoint whether it’s axonal or demyelinating, determine which nerves are involved, and track whether the condition is progressing.
In some cases, a small skin biopsy is used to count the density of tiny nerve fibers in the skin. This is especially useful for diagnosing small fiber neuropathy, which nerve conduction studies can miss because those tests primarily measure large fibers.
Treatment and Pain Management
The most important step in treating neuropathy is addressing the underlying cause whenever possible. For diabetic neuropathy, that means tightening blood sugar control to slow further damage. For B12 deficiency, it means supplementation, often by injection since poor absorption is usually the root problem. For alcohol-related neuropathy, treatment requires stopping alcohol use and restoring a balanced diet.
For neuropathic pain itself, standard pain relievers like ibuprofen or acetaminophen generally don’t work well. Instead, doctors turn to medications that calm overactive nerve signaling. The main first-line options fall into three categories: certain antidepressants that affect pain signaling pathways, anticonvulsant medications originally developed for seizures, and topical treatments applied directly to the skin. These medications don’t fix the damaged nerve but can significantly reduce the burning, shooting, or stabbing pain that interferes with daily life and sleep.
Topical options work best for localized pain. Lidocaine patches numb a specific area, while high-concentration capsaicin patches (applied under medical supervision) desensitize nerve endings over time. For widespread neuropathic pain, oral medications are more practical. Finding the right one often takes some trial and error, and many people benefit from combining approaches.
Physical therapy can help maintain strength and balance, particularly when motor nerves are involved. Occupational therapy may address difficulty with fine motor tasks like buttoning a shirt or using utensils.
Nerve Recovery and What to Expect
Peripheral nerves can regenerate, which sets them apart from nerves in the brain and spinal cord. But the process is slow. Nerves regrow at roughly 1 millimeter per day, which means that if a nerve is damaged at the knee, it could take a year or longer for the regenerating fiber to reach the foot muscles. During that time, muscles that have lost their nerve supply gradually weaken and can eventually be replaced by fatty tissue if reinnervation doesn’t happen in time.
Whether nerves recover at all depends heavily on the cause and severity. Neuropathy from a correctable deficiency, like B12 or thiamine, has a much better outlook than neuropathy from long-standing, poorly controlled diabetes where years of damage have accumulated. Chemotherapy-induced neuropathy often improves after treatment ends, but some people are left with permanent symptoms. In general, the earlier the underlying cause is identified and treated, the better the chance that nerve function can stabilize or improve.
Daily Foot Care for Sensory Loss
If you’ve lost sensation in your feet, daily inspection is essential. The American Diabetes Association recommends checking your feet every day, either by feeling them with your hands or using an unbreakable mirror to see the soles. You’re looking for cuts, blisters, red spots, swelling, or any change in skin color or temperature. Because you can’t rely on pain to alert you to a problem, your eyes and hands have to do that job instead.
Keep the skin moisturized to prevent cracking, especially on the heels, but avoid putting lotion between the toes where moisture can encourage fungal infections. Don’t trim ingrown toenails or shave calluses yourself. Wear shoes that fit well and check inside them before putting them on to catch any pebbles or rough spots that could cause an unnoticed injury. These precautions sound simple, but they are the most effective way to prevent the foot ulcers and infections that lead to serious complications.