Possible Causes of a Numb Thumb or Hand

Numbness and tingling in the hand isn’t often a cause of concern. However, if the numbness is caused by some medical issues, it can run from mild and temporary to a serious health condition. The common causes being compression or damage of the nerves in the hand. The hand is made up of very sensitive receptors which are connected to the brain through the nerves. Whenever a section of these nerves is damaged, the brain may not receive all the sensory info your hand is sending its way which results in numbness. Below are other possible causes of a numb thumb or hand.

1. Vitamin or Mineral Deficiency

Lack of enough vitamin B-12 can cause numbness or tingling effect on your hand. Your body requires vitamin B-12 for healthy nerves. Additionally, magnesium and potassium deficiency can result in numbness.

The following symptoms should also indicate that you’re lacking enough vitamin B-12:

  • Fatigue.
  • Yellow skin.
  • Weakness.
  • Trouble walking and balancing.
  • Difficulty thinking straight.
  • Hallucination.

2. Side Effects of Certain Medications

Nerve damage (neuropathy) is the common side effect of a drug that treats almost everything from seizure to cancer. This side effect can affect both your hands and feet. Other drugs that can cause numbness are:

  • Antiseizure drugs: phenytoin (Dilantin).
  • Antibiotics: metronidazole (Flagyl), nitrofurantoin (Macrobid) and fluoroquinolones (Cipro).
  • Anticancer drugs: cisplatin and vincristine.
  • Heart or blood pressure drugs: Amiodarone (Nexterone) and hydralazine (Apresoline). Sometimes you might experience the following symptoms of drug-induced nerve damage.
  • Tingling
  • Weakness
  • Abnormal feelings in your hands

3. Carpal Tunnel

Carpal tunnel is the most common cause of hand numbness according to doctors. This condition occurs when the median nerve, which supplies feelings to the fingers, including the thumb, index, middle and part of the ring finger, become pinched at your wrist. People who spend a lot of time working on a computer, especially if the set up demands you lay your wrist against an edge or hard surface, can easily suffer from carpal tunnel. Other symptoms of carpal tunnel include a sensation at one or more of your fingers.

4. Stroke

Once in a while, numbness in the hand isn’t something we pay much attention to. Although it’s unlikely, hand numbness could be a sign of a stroke. You need to take immediate action in case you experience any of the following symptoms:

  • Trouble speaking or understanding others
  • Confusion
  • Drooping of your face
  • Sudden trouble seeing out of one or both eyes
  • Sudden severe headache
  • Dizziness or loss of balance
  • Sudden weakness or numbness in your arm or leg

5. Diabetes

A diabetic person’s body can have a hard time moving sugar from the bloodstream into the cells. Long term high blood sugar can lead to nerve damage called diabetic neuropathy. Peripheral neuropathy can cause numbness in your arms, hands, legs, and feet too. You should look out for other symptoms of neuropathy such as:

  • Pins and needles feeling
  • Weakness
  • Pain
  • Loss of balance
  • Burning

6. Thyroid disorder

Thyroid gland in the neck is important in the production of hormones that regulate the body’s metabolism. When the thyroid produces too little of its hormone that condition is called underactive thyroid or hypothyroidism. If hypothyroidism goes untreated it can damage nerves that send feelings to your arms and legs, a condition called peripheral neuropathy. It leads to numbness, weakness, and tingling in your hands and feet.

7. Fibromyalgia

Fibromyalgia is characterized by fatigue and muscle pain. Sometimes people confuse it with chronic fatigue syndrome because both have similar symptoms. However, fibromyalgia fatigue is intense and the pain spreads through several points around the body. People suffering from fibromyalgia might experience numbness and a tingling sensation in their hands, feet, legs, and face. Apart from that, other symptoms include:

  • Trouble concentrating
  • Depression
  • Sleep problems
  • Headaches
  • Belly pain
  • Constipation
  • Diarrhea


If your numbness persists for more than three days and it doesn’t spread to other body parts, then you need to see a doctor. Also, in case, you had some injuries and you’re experiencing numbness due to that, then you need to see a doctor. Additionally, the pattern and distribution of symptoms can help you know if the cause is pressure on a nerve, a disease, medications, nutritional or other condition. When the cause is determined, undertaking necessary tests can help confirm a diagnosis. Luckily, numbness can resolve itself within a few minutes. There are other rare causes of thumb and hand numbness which include:

  • Vasculitis
  • Stage 4 HIV
  • Amyloidosis
  • Multiple sclerosis (MS)
  • Thoracic outlet syndrome
  • Guillain-Barre syndrome

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