Finger Numbness: What Causes Numb Fingers

Which fingers are numb? A quick guide to the cause

Three nerves supply feeling to the fingers. The pattern of numbness usually tells you which one is irritated.

Common causes of numb fingers

Carpal tunnel syndrome

The median nerve is squeezed as it passes through a tight tunnel at the wrist. Numbness and tingling affect the thumb to ring finger, typically waking you at night, and you may shake your hand to relieve it. Over time, the thumb can become weak and clumsy. Risk factors include repetitive wrist use, pregnancy, diabetes, hypothyroidism, rheumatoid arthritis and obesity. See carpal tunnel syndrome.

Cubital tunnel syndrome

The ulnar nerve (the "funny bone" nerve) is compressed at the elbow. Numbness affects the ring and little fingers, worse when the elbow is bent for long periods, such as holding a phone or sleeping with arms bent. Advanced cases weaken grip and the small hand muscles. See cubital tunnel syndrome.

Pinched nerve in the neck

Disc bulges or arthritis in the neck can press on nerve roots, causing neck pain that shoots down the arm into specific fingers, often worse when tilting the head back or to one side. See cervical radiculopathy.

Raynaud's phenomenon

In cold or stress, finger arteries spasm. The fingers turn white, then blue, and feel numb, then go red and throb as blood returns. It is usually harmless, but secondary Raynaud's can be linked to scleroderma or lupus. See Raynaud's phenomenon.

Other causes

• Peripheral neuropathy: usually starts in the feet. Numb fingertips in both hands appear later. Diabetes is the commonest cause.
• Vitamin B12 deficiency: numbness and tingling in hands and feet, fatigue and memory problems.
• Thoracic outlet syndrome: compression of nerves and vessels between the collarbone and first rib, causing numbness in the ring and little fingers with arm ache when lifting the arms.
• Vibration white finger: from years of using vibrating tools, with numbness and white fingers.
• Finger injuries: cuts or crushes can damage the small digital nerves.
• Cold injury: frostbite or frostnip.
• Medicines: some chemotherapy drugs.
• Multiple sclerosis, rarely starting with numbness in a hand.
• Stroke, when numbness is sudden and comes with other one-sided symptoms.
• Anxiety and over-breathing: tingling in both hands and around the mouth that fades as breathing settles.

How doctors diagnose the cause

A doctor will ask exactly which fingers are numb, when it happens, what makes it worse, and about neck pain, weakness, diabetes, thyroid problems and your work and hobbies. They will check sensation and strength in each finger, look for muscle wasting at the base of the thumb or between the fingers, and do provocative tests:

• Tinel's sign: tapping over the nerve at the wrist or elbow reproduces tingling.
• Phalen's test: holding the wrists flexed for 60 seconds brings on carpal tunnel symptoms.
• Elbow flexion test: bending the elbow fully brings on ulnar symptoms.
• Spurling's test: turning and pressing the head reproduces neck root symptoms.

Further tests include nerve conduction studies and EMG, ultrasound of the nerve, an MRI of the neck, and blood tests for glucose, B12, thyroid function and kidney function.

Treatment and home care

For nerve compression

• Wrist splints at night keep the wrist straight and are very effective for early carpal tunnel syndrome.
• Avoid prolonged elbow bending, use a headset instead of holding a phone, and do not lean on your elbows. A towel wrapped around the elbow at night can keep it straighter.
• Adjust activities: take breaks from repetitive gripping and vibrating tools, and use padded gloves for cycling.
• Steroid injection into the carpal tunnel can relieve symptoms for months.
• Surgery: carpal tunnel release or ulnar nerve decompression when symptoms are constant, there is weakness or muscle wasting, or conservative treatment fails.

For other causes

• keep hands warm and avoid smoking for Raynaud's, with medicines if attacks are severe
• physical therapy and posture changes for neck-related numbness
• blood sugar control and B12 replacement where relevant

Frequently asked questions

Why are my fingers numb?

The most common reason is a squeezed nerve: the median nerve at the wrist (carpal tunnel syndrome), the ulnar nerve at the elbow, or a nerve root in the neck. Other causes include Raynaud's phenomenon in the cold, diabetes, vitamin B12 deficiency and finger injuries.

What does numbness in the little finger mean?

Numbness in the little finger and half of the ring finger usually means the ulnar nerve is compressed, most often at the elbow (cubital tunnel syndrome). It can also come from a pinched nerve at the base of the neck or thoracic outlet syndrome. Persistent numbness or weakness should be assessed.

Why do my fingers go numb at night?

Night-time finger numbness is a classic sign of carpal tunnel syndrome, because the wrist often bends during sleep and squeezes the median nerve. Sleeping with bent elbows can also compress the ulnar nerve. A wrist splint worn at night usually helps.

Can finger numbness be a sign of a stroke?

Yes, though rarely by itself. A stroke causes sudden numbness or weakness, usually of the whole hand, arm or face on one side, often with speech or vision problems. Sudden numbness with any of these signs needs a 911 call. Gradual numbness in specific fingers is usually a nerve problem.

Should I worry about numb fingertips?

Brief numbness after cold or pressure is normal. See a doctor if numbness persists, keeps coming back, affects both hands, comes with weakness or clumsiness, or if fingertips change color in the cold. These patterns can point to nerve compression, neuropathy or Raynaud's.