The most common reason for getting a numb hand or arm is sitting or sleeping in the same position for a long time. That can put pressure on your nerves and cut off blood flow, which brings on short-term numbness.
Carpal Tunnel Syndrome
The carpal tunnel is the narrow passageway formed by connective tissue and small bones on the palm-side of your wrist. Tendons and your median nerve go through it.
Carpal tunnel syndrome happens when inflammation or a narrowing of your tunnel puts pressure on a nerve inside. Sometimes this happens because of hand and finger movements you do over and over.
Problems often start gradually. You may feel numbness in your thumb and the two fingers next to it. It can be painful, too. Your hand might feel weak and you might drop things.
If you think you have carpal tunnel syndrome, take breaks during repetitive movement to rest your hands. Avoid activities that make your symptoms worse, and use cold packs to ease pain and swelling.
See a doctor if these symptoms don't go away and they interrupt your sleep or daily activities. The doctor might recommend a splint, medicine, or surgery. Without treatment, carpal tunnel syndrome can cause permanent damage to nerves and muscles.
If your cartilage, muscles, or tendons put too much pressure on a nerve, it might not be able to work right. This can cause numbness.
If a pinched nerve made your arm numb, you might also have:
- Sharp aching or burning pain
- Tingling or "pins and needles" feeling
- Muscle weakness in your arm
- Frequent feeling that your hand has fallen asleep
Rest and over-the-counter pain relievers can help relieve your symptoms. If they don't, and your symptoms last more than a few days, see your doctor. They might recommend a splint, brace, physical therapy, medication, or surgery.
Migraine With Aura
If migraine with aura is the cause of your arm numbness, the symptoms usually start within an hour of the head pain. They last less than an hour.
Other aura symptoms include:
- Changes in vision or vision loss, including blind spots
- Seeing zigzag lines, flashes of light, or stars
- Muscle weakness
- Difficulty speaking or finding the right word
Your doctor can prescribe medications to treat and prevent migraines if over-the-counter pain relievers are not enough.
You should see your doctor if you have the symptoms of migraine with aura because some of these, such as vision problems, are also symptoms of a stroke or a torn retina.
High blood sugar levels can damage your nerves and cause a problem called diabetic neuropathy. You may get numbness that usually starts in both of your feet. In rare cases, it can affect your hands, too.
If you have diabetic neuropathy, you might also have:
- Tingling or burning
- Sharp pains or cramps
- Increased sensitivity to touch (the weight of your clothes or sheets could be painful)
- Muscle weakness
- Loss of reflexes, especially in the ankle
- Trouble with balance and coordination
- Serious foot problems, such as ulcers, infections, and bone and joint pain
If you think you have diabetic neuropathy, talk to your doctor about how to make improvements in your diabetes management.
Neurological conditions, such as multiple sclerosis (MS), can also cause arm numbness.
If a neurological problem is behind your arm numbness, you might also have:
- Numbness in your feet
- Problems speaking or concentrating
See a doctor to get treatment that can relieve symptoms, and, in some neurological conditions, help slow the progress of the disease.
Side Effects of Chemotherapy
Some types of chemotherapy for cancer can cause nerve damage that leads to numbness or tingling and pain in your arms, legs, fingers, toes, or other areas of your body. It's called the "glove and stocking sensation" because it can feel like a thick, tight glove.
Medications can relieve these symptoms, especially the pain.
This is a normal side effect of some chemotherapy, but you should talk to your doctor if it prevents you from doing your daily activities. It could take up to 2 years after chemotherapy for full feeling to return.
Besides numbness in your arms or legs, a stroke can cause weakness, confusion, problems seeing and speaking, and drooping on one side of your face. If you have any of these, call 911.
If you suspect you or someone you're with may have symptoms of a heart attack, call 911.