Neuropathy in the feet is most commonly triggered by prolonged high blood sugar, but it has dozens of other causes, from vitamin deficiencies to nerve compression to certain medications. About half of all people with diabetes eventually develop some form of peripheral neuropathy, making it the single largest driver. Understanding what’s behind your symptoms matters because many triggers are treatable or reversible when caught early enough.
How High Blood Sugar Damages Foot Nerves
Diabetes is responsible for more cases of foot neuropathy than any other condition. When blood sugar stays elevated over months or years, it sets off a chain of damaging events inside nerve cells: chronic inflammation, oxidative stress, and damage to the tiny blood vessels that supply nerves with oxygen and nutrients. Sugar molecules also bind to proteins in nerve tissue, creating compounds that stiffen and impair nerve fibers over time.
The longest nerves in the body are hit first, which is why symptoms almost always start in the feet and toes before working their way upward. Tingling, burning, numbness, or a feeling like you’re wearing socks when you’re not are typical early signs. The American Diabetes Association recommends that everyone with type 2 diabetes be screened for neuropathy starting at diagnosis, and everyone with type 1 diabetes starting five years after diagnosis, with at least annual checks from that point on. Screening typically involves pressing a thin filament against the sole of the foot to test whether you can feel light pressure, plus checks for vibration and temperature sensation.
The critical takeaway: blood sugar control is the most effective way to slow or prevent diabetic neuropathy. People with prediabetes can also develop nerve damage, so the threshold for harm is lower than many realize.
Vitamin Deficiencies, Especially B12
Your peripheral nerves are wrapped in a protective coating called myelin, and your body needs vitamin B12 to maintain it. When B12 drops low enough, that coating breaks down, producing numbness, tingling, and pain that often starts in the feet. The clinical cutoff for B12 deficiency is relatively low, and research published in Neurology suggests that levels nearly three times higher than that cutoff may actually be necessary for optimal nerve function, particularly in older adults.
B12 deficiency is especially common in people over 60 (who absorb it less efficiently), long-term users of acid-reducing medications, and those following strict vegan diets. Other nutritional gaps that can trigger foot neuropathy include deficiencies in vitamins B1, B6, and E, as well as copper. The good news is that nutritional neuropathy often improves once the deficiency is corrected, though recovery can take months.
Alcohol and Direct Nerve Toxicity
Up to half of long-term heavy drinkers develop alcoholic neuropathy. Alcohol appears to poison nerve fibers directly while also contributing to the poor nutrition that accelerates nerve breakdown. Most people with alcoholic neuropathy have been drinking heavily for years, though there’s no precise “safe” threshold below which nerve damage never occurs.
Symptoms follow the same feet-first pattern as diabetic neuropathy: burning or prickling in the soles, difficulty sensing temperature, and eventually muscle weakness. Stopping or significantly reducing alcohol intake is the only proven way to halt progression, though some nerve damage may be permanent by the time symptoms appear.
Chemotherapy and Other Medications
Certain cancer drugs are notorious for triggering neuropathy in the feet and hands. Platinum-based drugs, taxanes, vinca alkaloids, and several others all damage nerve cells through different mechanisms. Symptoms can appear quickly. With some platinum-based regimens, patients develop cold sensitivity, tingling, and pain that peaks two to three days after each infusion. Taxane-based drugs cause a similar acute pain pattern on the same timeline, though it was historically misidentified as joint or muscle soreness rather than nerve damage.
Chemotherapy-induced neuropathy sometimes resolves after treatment ends, but for a significant number of cancer survivors it persists for months or years. Beyond chemotherapy, other medications linked to foot neuropathy include certain antibiotics (particularly fluoroquinolones), some heart and blood pressure drugs, and anti-seizure medications.
Nerve Compression and Physical Injury
Not all foot neuropathy stems from a systemic condition. Sometimes the nerve itself is physically compressed or injured. Tarsal tunnel syndrome is a common example: the tibial nerve gets squeezed as it passes through a narrow channel on the inside of the ankle, producing burning, tingling, or numbness along the sole of the foot.
Several structural issues raise your risk. Flat feet and high arches both change how pressure is distributed across the ankle. Previous injuries like ankle sprains or fractures can cause swelling or scar tissue that crowds the nerve. Growths near the nerve, including cysts, bone spurs, or varicose veins, can also compress it. More than two in five people diagnosed with tarsal tunnel syndrome have a history of ankle injuries, according to Cleveland Clinic data, making it largely an overuse or post-injury condition. Treatment often focuses on reducing the compression through orthotics, physical therapy, or in some cases surgery.
Autoimmune and Inflammatory Conditions
Your immune system can sometimes turn against your own nerves. In chronic inflammatory demyelinating polyneuropathy (CIDP), the immune system attacks the myelin sheath surrounding peripheral nerves. Symptoms typically include weakness and sensory changes that start in the feet, progressing to difficulty walking, numbness, burning, and tingling that gradually moves upward into the legs and eventually the hands.
CIDP differs from most other causes of foot neuropathy in one important way: it tends to cause significant muscle weakness early on, not just sensory symptoms. Diagnosis usually involves nerve conduction studies (which measure how fast electrical signals travel through your nerves), electromyography, and sometimes a spinal tap or nerve biopsy. Other autoimmune conditions linked to foot neuropathy include lupus, rheumatoid arthritis, Sjögren’s syndrome, and vasculitis.
Infections That Target Nerves
Several infections can inflame or damage peripheral nerves. Lyme disease, caused by a tick-borne bacterium, can produce a condition called radiculoneuropathy when it reaches the nervous system. This causes numbness, tingling, shooting pain, or weakness in the limbs. The CDC notes that severe limb pain without a clear injury, in someone who lives in or has traveled to a Lyme-endemic area, should raise suspicion for neurologic Lyme disease.
Shingles, caused by reactivation of the chickenpox virus, can trigger intense nerve pain that persists long after the rash clears, a condition called postherpetic neuralgia. HIV, hepatitis C, and certain other viral infections also carry neuropathy risk, sometimes from the infection itself and sometimes as a side effect of antiviral treatment.
Other Common Triggers
Kidney disease allows toxins to accumulate in the blood that would normally be filtered out, and those toxins damage peripheral nerves over time. Thyroid disorders, particularly hypothyroidism, slow the metabolism in ways that can lead to fluid retention and nerve compression. Exposure to industrial chemicals, heavy metals like lead and mercury, and certain pesticides can also cause toxic neuropathy.
In roughly 30% of neuropathy cases, no clear cause is ever identified. This is called idiopathic neuropathy, and it’s more common in people over 60. Some of these cases may involve undiagnosed prediabetes or subclinical nutritional deficiencies that testing doesn’t catch.
How Foot Neuropathy Is Diagnosed
Diagnosis usually starts with a physical exam focused on sensation in your feet. Your doctor may press a thin nylon filament against the sole of your foot to check for loss of protective sensation, then test your ability to detect vibration, temperature, and pinprick. If you can’t feel the filament and at least one other test is abnormal, that confirms significant sensory loss.
If the cause isn’t obvious from your medical history, nerve conduction studies measure how quickly and strongly electrical signals travel along your nerves. Slower-than-normal signals point to damage in the nerve’s insulating layer, while weak signals suggest the nerve fibers themselves are deteriorating. Blood tests can check for diabetes, vitamin deficiencies, thyroid problems, kidney function, and markers of autoimmune disease. In less straightforward cases, a nerve biopsy or spinal fluid analysis may be needed to pin down the diagnosis.