Numbness in Feet: Causes, Tests and Treatment

What foot numbness feels like

People describe numb feet as feeling like:

• wearing thick socks when barefoot
• walking on cotton wool or cardboard
• feet that are "asleep" with pins and needles
• not being able to feel the floor or the temperature of bath water
• burning, electric or stabbing sensations (often with nerve damage)

Numbness matters because you may not notice cuts, blisters or burns, and you may lose balance.

Causes of numbness in both feet

When both feet are affected symmetrically, starting in the toes and creeping upward, the usual cause is peripheral neuropathy: damage to the longest nerves in the body.

• Diabetes: the most common cause. Diabetic neuropathy affects up to half of people with long-standing diabetes. It may also occur in prediabetes.
• Vitamin B12 deficiency: from pernicious anemia, a vegan diet, long-term metformin or acid-reducing medicines, or stomach surgery. It may also cause anemia, fatigue and poor balance.
• Alcohol: heavy long-term drinking damages nerves directly and through poor nutrition; see alcoholic neuropathy.
• Medicines: chemotherapy, some antibiotics, older HIV drugs, high-dose vitamin B6.
• Kidney disease, hypothyroidism, liver disease.
• Autoimmune and inflammatory conditions: Sjogren's syndrome, vasculitis, celiac disease, CIDP, Guillain-Barre syndrome.
• Inherited neuropathy: Charcot-Marie-Tooth disease, often with high arches and hammertoes.
• Infections: HIV, hepatitis C, Lyme disease, leprosy.
• Spinal stenosis or spinal cord problems: numbness in both legs with walking or with other signs.

In around a quarter of people, no cause is found (idiopathic neuropathy).

Causes of numbness in one foot

Accompanying symptoms and what they suggest

• Burning pain at night: small-fiber neuropathy, often diabetes
• Unsteadiness in the dark: loss of position sense, as with B12 deficiency or large-fiber neuropathy
• Back pain shooting down the leg: pinched nerve root
• Fatigue, pale skin, sore tongue: B12 deficiency
• Thirst, frequent urination, weight loss: undiagnosed diabetes
• Weakness and wasting: more advanced nerve damage

How doctors diagnose numb feet

The doctor will ask when it started, whether one or both feet are affected, how it has spread, and about diabetes, alcohol, diet, medicines, back pain and family history. They will check sensation (light touch, pinprick, vibration with a tuning fork, a monofilament test), reflexes, strength, pulses and the skin of the feet.

Tests often include:

• Blood tests: fasting glucose or HbA1c, vitamin B12 (with methylmalonic acid if borderline), thyroid function, kidney and liver function, full blood count and serum protein electrophoresis
• Nerve conduction studies and EMG: confirm neuropathy and distinguish nerve from root problems
• MRI of the spine if a pinched nerve root or spinal cord problem is suspected
• Ankle-brachial index if circulation is in doubt
• Skin biopsy for small-fiber neuropathy

Treatment

Treat the cause

• better blood sugar control in diabetes, which slows progression
• B12 injections or high-dose tablets for deficiency
• stopping alcohol and improving nutrition
• adjusting nerve-toxic medicines
• physical therapy, injections or surgery for nerve compression

Relieve nerve pain

Medicines used for painful neuropathy include duloxetine, pregabalin, gabapentin and amitriptyline. Topical capsaicin or lidocaine patches help some people. Ordinary painkillers usually help little.

Protect your feet

• check your feet every day for cuts, blisters and color changes, using a mirror if needed
• wear well-fitting shoes and socks, never walk barefoot
• test bath water with your elbow or a thermometer
• keep skin moisturized but dry between the toes
• have regular podiatry and diabetic foot checks

Prevent falls

Balance training, good lighting, removing trip hazards and using a cane or walker if needed reduce falls.

Frequently asked questions

Why are my feet numb?

The most common cause of numbness in both feet is peripheral neuropathy, frequently from diabetes, vitamin B12 deficiency, heavy alcohol use or medicines. Numbness in one foot is more often a pinched nerve in the back or leg, Morton's neuroma or tarsal tunnel syndrome. Persistent numbness needs testing.

Is numbness in feet a sign of diabetes?

It can be. Diabetic neuropathy typically starts as numbness, tingling or burning in the toes of both feet. Sometimes it is the first sign that leads to a diabetes diagnosis. A blood test for HbA1c or fasting glucose can check, especially if you also have thirst or frequent urination.

When should I worry about numbness in my feet?

Seek emergency care if numbness starts suddenly with weakness, speech problems or facial droop, rises quickly up the legs, or comes with numbness in the groin or loss of bladder or bowel control. See a doctor soon for any numbness lasting more than a few days.

Can a vitamin deficiency cause numb feet?

Yes. Vitamin B12 deficiency is a common, treatable cause of numbness and tingling in the feet, often with poor balance and fatigue. Deficiencies of thiamine (B1), copper and vitamin E can also damage nerves. Too much vitamin B6 can cause numbness too.

Can numbness in the feet be reversed?

It depends on the cause. Numbness from B12 deficiency, nerve compression or medicines often improves after treatment, though recovery can take months. Long-standing nerve damage from diabetes is usually permanent, but good blood sugar control can stop it from getting worse.