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.
Vitamin and Mineral Deficiencies
Low levels of several minerals, including calcium and phosphorus, may cause numbness in the fingers and feet. MedlinePlus notes that 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, according to Merck.
Stroke and TIA
Stroke and transient ischemic attack, or TIA, often cause numbness and tingling on one side of the body. A TIA, caused by temporary changes in the blood supply to the brain, produces stroke-like symptoms for up to 12 hours. A TIA may be a warning sign of an impending stroke, but it does not cause the same damage to the brain that a stroke causes.
General Medical Disorders
Various medical disorders may cause numbness in the fingers and feet, including hypothyroidism, shingles, Raynaud's phenomenon and migraines. Shingles is a disorder caused by the same virus, the herpes zoster virus, that causes chickenpox. After a period of dormancy, the virus wakes, affects the nerve roots and begins producing symptoms when the immune system is weakened due to another reason. 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. The National Institute of Arthritis and Musculoskeletal and Skin Diseases states that attacks of Raynaud's phenomenon may be triggered by cold or stress. Numbness is also a common symptom of diabetes.
Nerve Problems
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.
Medications, Toxins and Circulatory Problems
Medications, radiation therapy, tobacco use, alcohol abuse and frostbite may lead to loss of sensation in the fingers and feet. Circulatory disorders or impaired 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, according to MayoClinic.com, but this typically only occurs after months or years of exposure to the toxic metal.
