What is numbness?
Numbness is an abnormal condition in which a person feels tingling or a loss of sensation. Numbness can occur anywhere on the body, but it is most often felt in the extremities, such as the hands, feet, fingers, and toes.
There are many different causes of numbness. Numbness usually arises from a lack of blood supply to an area, nerve compression, or nerve damage. Numbness can also result from infection, inflammation, trauma, and other abnormal processes. Most cases of numbness are not due to life-threatening disorders, but it does occur with stroke and tumors.
Numbness is often associated with or preceded by pain-like pins-and-needles, prickling, or burning sensations called paresthesias. Whereas numbness is a loss of sensation, paralysis involves a loss of movement, with or without the loss of sensation. The goal of the clinical evaluation is to identify the root cause for the numbness.
Depending on the cause, numbness can disappear quickly, such as numbness in the hand and arm from sleeping on your arm that will fade away once you move your arm around. Chronic numbness in the legs or arms over a long period of time generally indicates some level of damage to the nerves, such as that due to diabetes or multiple sclerosis. Chronic numbness in the fingers may be due to nerve entrapment, as is the case in carpal tunnel syndrome.
Because numbness can be a symptom of an underlying disease, disorder or condition, you should talk with your medical professional about any unusual sensations that last more than a few minutes.
If you experience numbness with loss of bladder or bowel control, paralysis, confusion, weakness in the extremities or slurred speech, seek immediate medical attention (call 911) in an emergency facility.
What other symptoms might occur with numbness?
Numbness may also be described as a tingling sensation, and numbness after sitting in one position for a long period of time can lead to a pins-and-needles sensation. Numbness most often occurs in the arms, legs, hands and feet, but can happen anywhere in the body. You may experience additional symptoms along with numbness. Any symptoms you notice occurring with numbness can help your doctor make a diagnosis.
Symptoms that may occur along with numbness
Numbness may occur with other symptoms including:
Increased numbness or tingling while walking
Pain in other parts of the body
Pins-and-needles (prickling) sensation
Sensitivity to touch
Serious symptoms that might indicate a life-threatening condition
In some cases, numbness may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Get immediate help if you, or someone you are with, are exhibiting any of these life-threatening symptoms:
Abnormal pupil size or nonreactivity to light
Confusion or loss of consciousness for even a brief moment
Loss of bladder or bowel control
Loss of vision or changes in vision
Numbness following a head, neck, or back injury
What causes numbness?
Numbness can be a symptom of a wide variety of diseases, disorders or conditions that either restrict blood flow or cause injury to the nerves.
Temporary numbness can be due to any activity that causes prolonged pressure on a nerve or nerves, such as sitting cross legged or bicycling long distance. Numbness can occur with moderate to serious orthopedic or circulatory conditions, as well as conditions and diseases that damage the nervous system. In some cases, numbness is a symptom of a serious or life-threatening condition that should be evaluated as soon as possible in an emergency setting.
Circulatory causes of numbness
Numbness can be caused by lack of blood flow to an area due to such conditions as:
Arteriovenous malformation (tangled knot of arteries and veins)
Buerger’s disease (acute inflammation and clotting of arteries and veins)
Frostbite or extremely cold temperatures
Peripheral artery disease (PAD, also called peripheral vascular disease, or PVD, which is a narrowing of arteries due to a buildup of fat and cholesterol on the artery walls, which limits blood flow to the extremities)
Raynaud’s phenomenon (rare disorder that narrows blood vessels in the fingers and toes when they are exposed to cold, or sometimes from stress)
Orthopedic causes of numbness
Numbness may also occur due to moderate to serious orthopedic conditions that injure or damage the nerves including:
Back or neck injury
Bone fractures or a cast that is too tight
Degenerative disk disease
Nerve entrapment or nerve pressure
Neurological causes of numbness
Numbness caused by nerve compression or damage may be due to such conditions as:
Diabetic neuropathy (nerve damage due to high blood sugar levels associated with diabetes)
Encephalitis (inflammation of the brain due to a viral or bacterial infection)
Heavy metal poisoning such as lead poisoning
Hypothyroidism (underactive thyroid)
Multiple sclerosis (disease that affects the brain and spinal cord)
Peripheral neuropathy (disorder of the peripheral nerves that lie outside your brain and spinal cord)
Spinal cord injury or tumor
Systemic lupus erythematosus (a disorder in which the body attacks its own healthy cells and tissues)
Transverse myelitis (neurological disorder causing inflammation of the spinal cord)
Questions for diagnosing the cause of numbness
To diagnose your condition, your doctor or licensed health care practitioner will most likely ask you several questions related to your numbness including:
What is your workplace environment like?
Where are you feeling numb?
When did the numbness start?
How long does the numbness last?
Are there any activities that cause the numbness?
Are you experiencing other sensations, such as pain, burning or itchiness?
What are the potential complications of numbness?
Because numbness can be due to serious diseases, failure to seek treatment can result in complications and permanent damage. It is important to contact your health care provider when you experience any kind of numbness or other abnormal feelings. Once the underlying cause is diagnosed, it is important that you follow the treatment plan outlined by your health care provider to reduce your risk of potential complications including:
Adverse effects of treatment for numbness
Inability to breathe on your own
Inability to walk
Permanent loss of sensation
Poor quality of life