Numbness in only one foot: what it can mean

Numbness in one foot and not the other is a useful clue by itself. Doctors pay close attention to it because it changes which explanations are most likely.

Why one foot matters

Peripheral neuropathy, the body-wide nerve condition, typically affects both feet, because the longest nerves on both sides are hit first. It is typically symmetric.^[1] Tarsal tunnel syndrome, by contrast, usually affects one foot, and symmetrical symptoms in both feet point more often to neuropathy or a problem in the lower back.^[2] A single-foot pattern makes it more likely that one nerve is being irritated at one spot. Neuropathy isn’t ruled out, because it can coexist with a pinched nerve.^[3]

Where the pattern points

• Two neighboring toes, often the third and fourth, with burning in the ball of the foot. This is the typical picture of Morton’s neuroma, where numbness or burning radiates to the affected toes.^[4] See Morton’s neuroma.
• The toes and sole, spreading from the inner ankle. This can be tarsal tunnel syndrome, compression of the tibial nerve at the ankle.^[2] See tarsal tunnel syndrome.
• The web space between the big toe and second toe, with an ache on top of the foot. The deep peroneal nerve may be involved.^[5] See numb top of the foot.
• The top of the foot reaching the outer lower leg. This suggests the superficial peroneal nerve.^[6]
• Numbness plus weakness lifting the foot. The common peroneal nerve at the knee or the L5 nerve root in the back can cause both numbness and foot drop.^[7,8] See foot drop.
• Numbness with pain from the back or buttock. A pinched nerve root in the lower back is the classic cause of sciatica.^[9,10] See sciatica or a foot nerve problem?
• Numbness that began after an injury or an operation. The nerve may have been stretched, bruised or caught in scar tissue. See nerve pain after surgery or injury.
• A cold, pale or bluish foot, or calf pain with walking that eases with rest. Reduced circulation has its own evaluation.^[11]

More than one cause can be present at once, so this list is a guide and not a diagnosis.

What the evaluation looks at

• Your story: which toes, how it began, what brings it on, your footwear, back or buttock pain, injuries and surgery.
• An examination of the whole leg, not just the foot: sensation, strength, reflexes, tapping along the nerves that commonly cause trouble, the back, hip and knee, and circulation.
• Tests when they would change the plan. Nerve studies can help show whether the trouble is at the nerve root, along the nerve in the leg, or in the foot, though they can be normal in people who do have a nerve problem.^[12,7] Ultrasound or MRI can show what is pressing on a nerve.^[13] These are arranged with other specialists and reviewed with you. See nerve testing for foot pain.

What you can do while you wait

• Try roomy shoes with a wide toe box and a low heel, and loosen tight lacing.
• Look at both feet every day for cuts, blisters or color changes. Numb skin is easy to injure without noticing.
• Note which toes are affected and what makes them better or worse.

Many foot and ankle nerve entrapments improve with non-surgical care, and surgery is reserved for cases that do not respond.^[14]

When to see a specialist

Consider an evaluation if numbness in one foot lasts more than a few weeks, keeps returning, is spreading, or affects your walking or balance. If you have diabetes, have new numbness checked promptly.