The most common cause of nerve damage in the feet is prolonged high blood sugar from diabetes, but it’s far from the only one. Peripheral neuropathy affects about 2.4% of the general population and rises to over 8% in people older than 55. Diabetes accounts for roughly 32% to 53% of all cases, which means a significant portion stems from other causes: nutritional deficiencies, alcohol use, autoimmune conditions, infections, medications, and physical compression of the nerves themselves.
How Diabetes Damages Foot Nerves
Diabetes is the single biggest driver of nerve damage in the feet, and the mechanism goes deeper than “high blood sugar is bad for you.” When blood sugar stays elevated, glucose floods into the supportive cells that wrap around nerve fibers. Inside those cells, the excess sugar gets converted into sorbitol and fructose through a chemical pathway that generates oxidative stress, essentially producing toxic byproducts that damage the cells from within. As these supportive cells break down, the nerve fibers they protect lose their insulation and structural support.
At the same time, high blood sugar damages the tiny blood vessels that supply nerves with oxygen. The walls of these capillaries become less permeable, reducing oxygen delivery to nerve tissue. This creates a kind of slow suffocation: the nerves can’t get the fuel they need, and the resulting low oxygen environment impairs their ability to function. The combination of metabolic poisoning and oxygen starvation is why diabetic neuropathy tends to progress gradually and why it hits the feet first, since those nerves are the longest in the body and most vulnerable to supply disruptions.
About 50% or more of people with diabetes develop peripheral neuropathy over the course of the disease, and the risk increases the longer someone has diabetes. Current guidelines recommend screening for neuropathy starting at the time of a type 2 diabetes diagnosis (or five years after a type 1 diagnosis), with annual checks thereafter. These screenings typically involve a monofilament pressed against the foot to test sensation, vibration testing with a tuning fork, and checks for temperature or pinprick sensitivity.
Vitamin B12 Deficiency
Your nerves depend on a fatty coating called the myelin sheath to transmit signals efficiently, and vitamin B12 plays a direct role in maintaining it. B12 is needed to produce a molecule called SAM, which serves as the raw material for chemical reactions that keep myelin intact. When B12 levels drop too low, those maintenance reactions stall, and the myelin coating starts to deteriorate. Without it, nerve signals slow down or misfire, producing numbness, tingling, and burning sensations that often start in the feet.
More recent research suggests B12 deficiency also disrupts the balance of immune signaling molecules and growth factors that protect nerve cells. Some of these molecules are nourishing to nerves, others are toxic, and B12 deficiency tips the scale toward the toxic ones. This makes B12-related neuropathy a two-pronged problem: the protective coating degrades while the chemical environment around the nerve becomes hostile. People at highest risk include older adults (who absorb B12 less efficiently), vegans, those with digestive conditions that impair absorption, and long-term users of acid-reducing medications.
Alcohol-Related Nerve Damage
Heavy, sustained alcohol use is one of the more common non-diabetic causes of foot neuropathy. Alcohol is directly toxic to nerve fibers, and chronic exposure gradually destroys the small sensory nerves in the extremities. But alcohol also causes nerve damage indirectly by interfering with nutrient absorption, particularly B vitamins, creating a compounding effect where the nerves are being poisoned and starved of protective nutrients simultaneously.
The damage typically develops over years of heavy drinking rather than from a single binge. It tends to start with burning or prickling in the feet and can progress to numbness, difficulty walking, and muscle weakness. Because alcohol-related neuropathy involves both direct toxicity and nutritional deficiency, treatment usually requires stopping or sharply reducing alcohol intake while aggressively replenishing B vitamins.
Chemotherapy and Other Medications
Certain cancer treatments are notorious for causing nerve damage in the feet and hands, a condition known as chemotherapy-induced peripheral neuropathy. The classes of drugs most likely to cause it include taxanes (used for breast and ovarian cancers), platinum-based drugs (used for lung, colon, and other cancers), vinca alkaloids, thalidomide, and bortezomib.
The numbers are striking: approximately 68% of patients experience neuropathy symptoms one month after completing chemotherapy. That number drops to 60% at three months and 30% at six months, meaning the damage partially resolves for many people but persists long-term for a significant minority. Taxanes and platinum derivatives carry the highest risk. The damage can range from mild tingling to severe numbness that affects balance and daily function. For some patients, neuropathy becomes severe enough that doctors need to adjust or pause treatment.
Beyond chemotherapy, other medications can contribute to foot nerve damage. Long-term use of certain antibiotics, antivirals, and heart medications has been linked to peripheral neuropathy, though these are less common causes.
Autoimmune Conditions
In autoimmune-related neuropathy, the immune system mistakenly attacks the body’s own nerve tissue. Guillain-Barré syndrome is one of the more dramatic examples. It often begins in the feet, with weakness that can climb upward to affect the legs, arms, face, and even breathing muscles. Most people reach their weakest point within the first two weeks, and by the third week, 90% of those affected are at peak severity.
The hallmark of Guillain-Barré is that it comes on fast (over hours to days) and affects both sides of the body symmetrically. Diagnostic testing typically reveals slowed nerve conduction due to damage to the myelin sheath, along with elevated protein levels in the spinal fluid. While Guillain-Barré is relatively rare, other autoimmune conditions like lupus, rheumatoid arthritis, and chronic inflammatory demyelinating polyneuropathy (CIDP) can also damage foot nerves, usually with a slower, more gradual course.
Nerve Compression in the Foot
Not all nerve damage comes from systemic disease. Sometimes nerves in the foot get physically pinched or compressed. Tarsal tunnel syndrome is the foot’s equivalent of carpal tunnel in the wrist. The tibial nerve runs through a narrow passageway on the inner side of the ankle, and anything that crowds or presses on that space can cause pain, tingling, or numbness along the bottom of the foot.
Common causes of compression include flat feet or fallen arches (which stretch the tibial nerve), ankle sprains that cause swelling, ganglion cysts, varicose veins, swollen tendons, and bone spurs. Arthritis and diabetes can also create swelling that compresses nerves in this area, meaning compression can be a secondary consequence of other conditions on this list.
Infections That Target Nerves
Several infections can damage peripheral nerves, though they’re less common causes in developed countries. Lyme disease, spread by tick bites, can cause a condition called radiculoneuropathy, producing numbness, tingling, shooting pain, or weakness in the arms or legs. About 4 out of every 100 reported Lyme cases involve this type of nerve involvement. The pain tends to be severe and can mimic a herniated disc or other spinal problem, which sometimes delays the correct diagnosis.
Shingles, caused by reactivation of the chickenpox virus, can damage nerves and leave behind lasting pain known as postherpetic neuralgia. HIV, hepatitis C, and leprosy are other infections associated with peripheral nerve damage, each through different mechanisms ranging from direct viral attack on nerve cells to immune-mediated inflammation.
Other Contributing Factors
Several additional conditions can cause or contribute to nerve damage in the feet. Kidney disease allows toxins to build up in the blood that are harmful to nerve tissue. Hypothyroidism causes fluid retention that can compress nerves and slows the metabolic processes nerves depend on. Exposure to heavy metals like lead, mercury, and arsenic damages nerves directly. Even prolonged pressure on a nerve from a cast, crutches, or repetitive positioning can cause localized damage.
In roughly 30% of peripheral neuropathy cases, no identifiable cause is found. This is called idiopathic neuropathy, and it’s more common in older adults. While the lack of a clear cause can be frustrating, the symptoms are managed the same way regardless: controlling pain, protecting the feet from injury (since reduced sensation raises the risk of unnoticed wounds), and addressing any reversible contributing factors like blood sugar control or nutritional deficiencies.