Causes of Numbness and Tingling

Numbness is a loss of sensation in a part of the body, most typically in the hands or feet. Numbness is often accompanied by tingling—a “pins and needles” sensation. While most of the time these symptoms are due to a transient, benign cause, they sometimes indicate a serious medical problem and need to be evaluated by a physician.

What Causes Numbness?

Usually, numbness is caused by irritation of, or damage to, a particular nerve, or several nerves. The peripheral nerves (nerves that connect the brain and spinal cord to the rest of the body) are generally affected. In some cases, the affected nerves may be located in the brain or spinal cord.

There is a host of conditions that can affect peripheral nerves and produce numbness. Many times it is pretty easy for you or your healthcare provider to figure out what has caused the problem, but other times an extensive medical evaluation may be required. Causes of numbness include:

A Limb Falls Asleep

By far the most common cause of numbness and tingling occurs when an arm or a leg “falls asleep” after being held in an unusual position for too long. Most of us have awakened at one time or another with a “dead arm” because we fell asleep with our arm bent beneath our heads. This condition is caused by abnormal pressure on a nerve, and is quickly resolved by moving the affected limb back to a normal position for a few minutes, and letting the nerve recover. This condition is usually benign. However, if it does not improve over minutes or persists, sometimes there is lasting damage. Also, if it keeps happening, with little pressure, it could be a sign of a congenital disorder like marie-charcot or others.

Repetitive Nerve Damage

In a similar manner, other types of numbness and tingling may be related to localized nerve damage caused by repetitive actions. The most common of these is carpal tunnel syndrome, which is produced by repetitive pressure on the median nerve and is most often seen today in people who spend much of their time using a keyboard.

Carpal tunner syndrome (and similar syndromes affecting other nerves) can also be seen in pregnant women as well cyclists, carpenters, meatpackers, and many others whose jobs or hobbies involve repetitive actions that place pressure on a particular nerve. Treatment includes rest, intermittent breaks, the use of splints, localized treatment with ice, anti-inflammatory medication, physical therapy, and changing the way the repetitive action is performed in order to reduce pressure on the affected nerve. Rarely, surgery is needed.

Neurological Conditions

On the other hand, numbness and tingling may be related to an underlying neurological disorder, and may not be so benign. Almost any neurological problem can produce numbness and tingling. If so, the symptoms of numbness and tingling may be a warning sign that something very serious is going on. Here is a partial list of some of the more prominent conditions that produce nerve problems leading to numbness and tingling:

• Diabetes
• Alcohol abuse
• Aortic aneurysm
• Spinal disorders (including herniated disc)
• Multiple sclerosis
• Aortic aneurysm
• Stroke
• Transient ischemic attack
• Peripheral neuropathy
• Raynaud disease
• Shingles
• Lyme disease
• Toxin exposure
• Surgery
• Vasculitis
• Cancer chemotherapy

While numbness is usually caused by problems affecting the peripheral nerves, occasionally it can be produced by disorders affecting the central nervous system. Brain tumors, aneurysms, or arteriovenous malformations can sometimes cause numbness.

When Should You See a Healthcare Provider?

It is not necessary to see a medical professional when a limb falls asleep for a readily identifiable cause, and the symptoms go away immediately when you relieve the obvious cause. It also may not be necessary to see a healthcare provider if you have early symptoms of carpal tunnel syndrome, as long as you take steps to relieve the condition and reduce the chronic pressure on your median nerve.

But if you are experiencing numbness and tingling without an obvious reversible cause, you need to see your practitioner. The list of conditions that can produce these symptoms is quite large, and many of these conditions require treatment not only to relieve the symptoms you are experiencing but also to prevent much more serious problems from developing.

A Word From Verywell

Numbness is a common symptom, and usually, the cause is obvious to us and is completely reversible. But if you should experience numbness for no apparent reason, especially if it persists or keeps coming back, it is time to see your healthcare provider and have a medical evaluation.