Recurring numbness in your hands and feet usually points to a problem with the peripheral nerves, the long fibers that carry sensation between your brain and your extremities. Because these nerves are the longest in your body, they’re the most vulnerable to damage, and the feet are almost always affected first. The pattern of both hands and feet going numb is common enough that doctors have a specific term for it: peripheral neuropathy. Dozens of conditions can cause it, but a handful account for the vast majority of cases.
Diabetes Is the Most Common Cause
Diabetes is the leading cause of peripheral neuropathy in the United States. Roughly two-thirds of people with diabetes develop some degree of nerve damage, and about half will experience it in their lifetime. Persistently high blood sugar damages the small blood vessels that feed your nerves, slowly starving them of oxygen and nutrients. The tingling or numbness typically starts in the toes and feet, then creeps upward. If it progresses far enough, the hands become involved too.
You don’t need a formal diabetes diagnosis to be at risk. Prediabetes can cause nerve damage well before blood sugar levels cross the threshold for a diabetes diagnosis. Poor blood sugar control over time, older age, obesity, and high blood pressure all increase the likelihood of developing neuropathy. Keeping blood sugar well managed has been shown to slow nerve damage and, in some cases, encourage nerve regeneration.
Vitamin Deficiencies That Damage Nerves
Your nerves depend on B vitamins to build and maintain their protective coating, called the myelin sheath. Without enough of these vitamins, that coating breaks down and signals don’t travel properly. Vitamin B12 is the most important one. It’s essential for myelin synthesis and stabilization, and a deficiency is strongly linked to neuropathy. One large review of 32 studies found that neuropathy risk increased significantly when B12 levels dropped below about 205 ng/L.
B12 deficiency is especially common in people over 60, vegans and vegetarians (since B12 comes almost exclusively from animal products), and anyone taking long-term acid reflux medications, which interfere with B12 absorption. Vitamins B1 and B6 also play roles in nerve health. Interestingly, too much B6 from supplements can itself cause numbness, so more isn’t always better. A simple blood test can check your levels, and supplementation often improves symptoms if a deficiency is the root cause.
Nerve Compression Syndromes
Sometimes the problem isn’t widespread nerve damage but physical pressure on a specific nerve. Carpal tunnel syndrome compresses the median nerve at the wrist, causing numbness in the thumb, index, and middle fingers. Tarsal tunnel syndrome does something similar at the ankle, compressing the tibial nerve and causing numbness in the heel or sole of the foot. If you’re experiencing numbness in both your hands and feet, having both of these simultaneously is possible but less common than a systemic cause like neuropathy.
Nerve compression tends to follow predictable patterns. The numbness is usually limited to the area that specific nerve serves, it often worsens with certain positions or repetitive motions, and it may come with aching or weakness in the affected hand or foot. If the pattern of your numbness is more diffuse, affecting your entire hand or foot rather than specific fingers or patches, a compression syndrome is less likely to explain it.
Raynaud’s Phenomenon
If your numbness mainly strikes when you’re cold or stressed, Raynaud’s phenomenon could be responsible. In people with Raynaud’s, the blood vessels in the hands and feet overreact to cold temperatures or emotional stress, clamping down far more aggressively than normal and staying constricted for an extended period.
A typical episode follows a distinctive color sequence. The affected fingers or toes first turn white or pale as blood flow cuts off. They then shift to blue as the remaining blood loses its oxygen, and the area feels cold and numb. When blood flow returns, the skin flushes red and you may feel throbbing or tingling. Episodes are usually triggered by cold air, holding a cold drink, or reaching into the freezer, though emotional stress can also set them off. Raynaud’s can occur on its own or as part of an autoimmune condition like lupus or scleroderma.
Autoimmune and Inflammatory Conditions
Your immune system can directly attack the nerves themselves. In Guillain-Barré syndrome, the immune system targets peripheral nerves, often after an infection, causing rapidly progressive weakness and numbness that typically starts in the feet and moves upward. A related condition, chronic inflammatory demyelinating polyneuropathy (CIDP), causes a slower, longer-lasting version of the same kind of damage, stripping away the protective myelin coating around nerves over weeks to months.
Other autoimmune diseases like lupus and rheumatoid arthritis can cause neuropathy either by directly inflaming nerves or by causing swelling in surrounding tissues that compresses them. If your numbness appeared alongside joint pain, fatigue, skin rashes, or unexplained fevers, an autoimmune condition is worth investigating.
Medications and Toxic Exposures
Several common medications list neuropathy as a side effect. Chemotherapy drugs are the most well-known culprits. Chemotherapy-induced peripheral neuropathy is a recognized and sometimes disabling complication of cancer treatment. Certain medications for HIV, heart conditions, seizures, and infections can also damage nerves over time. If your numbness started after beginning a new medication, that connection is worth raising with your doctor.
Heavy metals are another overlooked cause. Mercury exposure, most often through contaminated fish or inhaled vapor in occupational settings, can cause numb limbs along with muscle weakness and coordination problems. Arsenic, typically encountered through contaminated water or food, produces a pricking sensation in the hands and legs. Lead exposure remains a concern in older homes and certain industrial jobs. These toxins enter the body through drinking water, food, air, or skin contact and accumulate over time.
Excess alcohol deserves its own mention. Heavy drinking damages nerves directly and worsens other conditions that cause neuropathy, including diabetes and nutritional deficiencies. Alcohol-related neuropathy is one of the more common forms doctors see.
How Doctors Figure Out the Cause
Because so many conditions cause the same symptom, your doctor will typically start with blood tests to check for diabetes, vitamin deficiencies, thyroid problems, and markers of autoimmune disease. If the cause isn’t obvious from bloodwork, nerve-specific testing comes next.
The two main tests are a nerve conduction study, which measures how fast electrical signals travel through your nerves, and electromyography (EMG), which records the electrical activity in your muscles at rest and during use. Together, these tests can pinpoint where the nerve damage is, how severe it is, and whether the problem is in the nerve fibers themselves or in their protective myelin coating. The distinction matters because it narrows down the list of possible causes considerably.
What Actually Helps
The most effective treatment depends entirely on the underlying cause. Correcting a B12 deficiency, getting blood sugar under control, or stopping an offending medication can halt the damage and sometimes reverse it. But regardless of the cause, several lifestyle changes have strong evidence behind them.
Regular exercise, particularly walking and swimming, can reduce neuropathy pain, improve muscle strength, and help control blood sugar. A diet rich in fish, nuts, whole grains, and fresh produce supports nerve health and corrects nutritional gaps. Limiting alcohol to moderate levels (one drink per day for women, two for men 65 and younger) removes a common source of ongoing nerve injury.
Foot care becomes especially important when numbness reduces your ability to feel pain. Small cuts, blisters, or pressure sores can go unnoticed and become serious infections. Checking your feet daily, wearing well-fitting shoes, and treating wounds promptly helps prevent complications that can escalate quickly.
Symptoms That Need Urgent Attention
Most cases of hand and foot numbness develop gradually and aren’t emergencies, but certain patterns demand immediate medical evaluation. Sudden numbness on one side of your body, especially with confusion, speech difficulties, or facial drooping, can signal a stroke. Rapidly progressive weakness moving upward from the feet over days, particularly after a recent infection, is a hallmark of Guillain-Barré syndrome. Numbness accompanied by loss of bladder or bowel control suggests pressure on the spinal cord.
Other red flags include unexplained weight loss, fever, or a history of cancer or immunosuppression alongside new numbness. These combinations can point to conditions that worsen quickly without treatment.