Paresthesia

Paresthesia is an abnormal sensation, usually unpleasant, that results from injury to nerves. It is usually described as a numb, prickly, stinging or burning feeling. It is typified by the sensation one feels when impacting the exposed nerve in the elbow, or "hitting the funny bone". It is also described as "pins and needles" or having a limb "fall asleep"
Paresthesia is usually transient and resolves itself without any treatment or even any effort whatsoever. Although it can arise from a panic attack, its usual cause is putting pressure on one of the nerves to the hands or feet. 
Long term paresthesia usually indicates a more serious condition, such as poor blood circulation (particularly in the elderly), vitamin deficiency, metabolic disorders or even generalized inflammation. More rarely, it is caused by a neuropathy, but this is also a more serious condition.
More on paresthesia at Wikipedia
Category:Symptoms