Numbness is a symptom associated with a plethora of diseases and disorders. Transient numbness not accompanied by pain or changes in skin color may be a normal response to cold temperatures or other benign conditions. Persistent or recurrent numbness, however, always requires medical attention. Unless other symptoms are present, extensive testing and evaluation may be necessary before the underlying cause of the symptom is uncovered.
Various medical disorders, such as shingles, Raynaud's phenomenon, and diabetes may cause numbness in the fingers and feet. Shingles is a disorder caused by the same virus -- herpes zoster -- that causes chickenpox. After a period of dormancy, the virus is activated. This can cause numbness and tingling in the affected area of the body. Raynaud's phenomenon is a disorder that causes constriction of the blood vessels in the extremities, usually the toes and fingers, resulting in episodic attacks of numbness. Attacks of Raynaud's phenomenon may be triggered by cold or stress. Numbness is also a common symptom of diabetes -- over time, nerves become damaged due to prolonged exposure to high blood sugar levels.
Multiple sclerosis is a progressive disorder characterized by damage to the myelin in the central nervous system. This damage interferes with the transmission of nerve signals and may cause numbness and tingling in the extremities. Other possible causes of numbness in the fingers and feet include seizure disorders; pressure on peripheral nerves caused by tumors, scar tissue, enlarged blood vessels or infection; or pressure on the nerves in the spine. Stroke and transient ischemic attack, or TIA, often cause numbness and tingling on one side of the body due to altered blood flow in the brain. Because stroke is potentially life-threatening, seek medical attention immediately if you have these symptoms.
Vitamin and Mineral Deficiencies
Low levels of several minerals, including calcium and phosphorus, may cause numbness in the fingers and feet. Vitamin B12 deficiency, or pernicious anemia, and some other vitamin deficiencies may also cause numbness in the extremities. Blood tests are effective at determining what deficiencies are present so that dietary changes, supplementation or other treatment options can correct the underlying deficiency and ease symptoms. Low calcium often occurs in conjunction with vitamin D deficiency, and both problems require correction before a complete resolution of symptoms is possible.
Medications, radiation therapy, tobacco use, alcohol abuse and frostbite may lead to loss of sensation in the fingers and feet. Decreased circulation due to sitting or standing for prolonged periods may lead to temporary or intermittent numbness. Nerve damage due to lead poisoning is another potential cause, but this typically only occurs after months or years of exposure to the toxic metal.
- Pharmacy and Therapeutics: Presentation and Management of Herpes Zoster (Shingles) in the Geriatric Population
- Diabetes Care: Diagnosis and Classification of Diabetes Mellitus
- The National Diabetes Information Clearinghouse: Diabetic Neuropathies -- The Nerve Damage of Diabetes
- Oregon State University, Linus Pauling Institute: Phosphorus
- National Institute of Arthritis and Musculoskeletal and Skin Diseases: Raynaud's Phenomenon
- National Multiple Sclerosis Society: Symptoms of Multiple Sclerosis
- National Institute of Neurological Disorders and Stroke: NINDS Shingles Information Page
- Centers for Disease Control and Prevention: Lead Poisoning