Paresthesia is a term that refers to an abnormal burning or prickling sensation which is generally felt in the hands, arms, legs, or feet, but may occur in any part of the body. The sensation, which arises spontaneously without apparent stimulus and is usually not painful, may also be described as tingling or numbness, skin crawling, buzzing, or itching.
Most people have experienced transient (temporary) paresthesia at some time in their lives; it occurs whenever inadvertent pressure is placed on a nerve and causes what many describe as a "pins and needles" feeling. The feeling quickly goes away once the pressure is relieved. For some people, however, paresthesia can become a chronic condition caused by an underlying disorder. It more frequently occurs as a symptom of more widespread neurological disease or traumatic nerve damage.
Paresthesia can be caused by disorders affecting the central nervous system, such as stroke, transient ischemic attack, multiple sclerosis, transverse myelitis, and encephalitis. A tumor or vascular lesion such as an arteriovenous malformation pressed up against the brain or spinal cord can also cause paresthesia. A wide range of conditions including diabetes, hypothyroidism, vitamin B12 deficiencies, alcoholism, heavy metal poisoning (lead, arsenic, and other metals), and nerve entrapment syndromes, such as carpal tunnel syndrome, can also damage peripheral nerves (peripheral neuropathy) and cause paresthesia. Connective tissue disorders such as rheumatoid arthritis or systemic lupus erythematosus also can cause peripheral neuropathy and lead to paresthesia.
Paresthesia caused by peripheral neuropathy may be accompanied by pain. Diagnostic evaluation is largely based on determining the underlying condition causing the paresthetic sensations. An individual's medical history, physical examination, and laboratory tests are essential for the diagnosis. Physicians may order additional tests depending on the suspected cause of the paresthesia.
