An unusual feeling. There are a variety of abnormal sensations. Tingling, an abnormal, prickling feeling in the skin, can be a sign of damage or irritation to nerves in the affected area. It is a different problem than numbness, which suggests instead that a nerve is damaged. A brief tingling sensation, as when a person’s hand or foot “falls asleep,” is not a cause for concern. However, a persistent tingling or pins and needles sensation may be caused by medical problems such as nerve injury; lack of blood supply; diabetes mellitus, type 1 and type 2; thyroid problems; vitamin Bl2 (cyanocobalamin) deficiency; carpal tunnel syndrome; transient ischemic attack; stroke; or multiple sclerosis. People with epilepsy may experience auras of unusual smells, unusual visual perceptions, or unusual tastes, all of which are also abnormal sensations.