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What causes numbness in the left arm and hand?

Dr Gareth

Medically reviewed by Gareth James, GP, GMC, DRCOG, DFFP, MRCGP on March 28, 2023. To give you technically accurate, evidence-based information, content published on the Check My Body Health blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

Numbness in the left arm and hand can be caused by a variety of conditions, some of which can be serious. Some common causes of numbness in the left arm and hand include:

Cervical radiculopathy: This occurs when a nerve root in the neck is compressed, potentially causing symptoms such as potentially causing symptoms such as pain, tingling, and numbness in certain fingers (defending which nerve is being compressed).

Carpal Tunnel Syndrome: This is a condition that occurs when the median nerve, which runs from the forearm into the hand, is compressed or pinched in the carpal tunnel, a small passageway on the palm side of the wrist.

Peripheral neuropathy: This is a condition that affects the nerves in the peripheries of the body, such as the arms and legs. It can be caused by a variety of factors, including diabetes, alcohol abuse, and certain medications. The symptoms of numbness, tingling burning or stabbing depend on which of the peripheral nerves are affected

Thoracic outlet syndrome: This is a less common condition that occurs when the blood vessels or nerves in the thoracic outlet, the space between the collarbone and the first rib, become compressed.

Stroke: Stroke can cause numbness, tingling, or weakness on one side of the body.

Spinal cord injury or herniated disk: A large disc herniation or a injury (such as from an RTA) may cause a compression of the spinal cord within the spinal canal causing numbness, stiffness, and potentially, depending on where the problem occurs may manifest itself with bowel and bladder control difficulties, which would indicate a medical emergency.

It’s important to note that this is not a complete list and that other causes such as Vitamin B12 deficiency, infections, tumours (benign and malignant), hormonal imbalances, or other underlying conditions could also lead to numbness in the left arm and hand. If you have persistent or severe numbness or other symptoms, it’s important to seek medical attention. A healthcare professional will be able to conduct a physical examination, take a medical history, and may order blood tests, imaging tests or other diagnostic tests to identify the underlying cause of your symptoms and recommend the appropriate treatment.

What to do if you experience numbness or tingling in the left arm

If you experience numbness or tingling in your left arm, it’s important to seek medical attention as soon as possible to determine the underlying cause and receive appropriate treatment.

Here are a few things you can do in the meantime:

Rest: Try to avoid activities that may aggravate the condition or cause further injury.

Apply heat or cold: Use a heating pad or ice pack to help reduce pain and inflammation.

Over-the-counter pain medication: Take over-the-counter pain medication, such as ibuprofen, to help alleviate discomfort.

Positioning: Changing your position can help alleviate symptoms of numbness or tingling.

Physical therapy: Specific exercises or stretches might help relieve symptoms.

It’s important to keep in mind that self-treatment can be helpful for certain conditions, however, it’s important to get a proper diagnosis and follow your healthcare professional’s advice should your symptoms not improve.

If your numbness or tingling is accompanied by other symptoms such as chest pain, difficulty breathing, or sudden weakness, it is important to seek medical attention immediately as it may be a symptom of a serious condition such as stroke or heart attack.


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