Parasathesia, which is actually correctly spelled paresthesia, is a temporary change in sensation which is not accompanied with long term damage or changes. However, chronic episodes can indicate that someone is experiencing a neurological problem which should be addressed, with the changes in sensation being the symptom of a serious underlying problem. Many people experience some degree of parasthesia at some point in their lives.
In some cases, parasthesia involves a prickling or tingling sensation. People can also experience a brief wave of heat or coolness, or numbness, in which they feel nothing in the affected area. Skin crawling or itching sensations can also characterize parasthesia in some cases. Usually, the sensation disappears after a few moments, leaving behind no noticeable change.
Transient parasthesia occurs briefly and in response to an environmental cause. For example, someone who unzips a tight pair of pants might experience a pins and needles sensation around the waist for a moment. Limbs which “fall asleep” are another example of transient parasthesia. Pinching nerves in the neck or along a limb can cause a case of transient parasthesia.
Chronic parasthesia is a neurological problem, caused by an error in the neurons which transmit signals throughout the nervous system. It is usually a symptom of a problem like poor circulation, inflammation, or a medical condition which can range from a tumor in the brain to a pinched nerve in the spinal cord. This type of sensation change will appear for sustained periods, and it will continue to appear over and over again in the same place, unlike a transient change in sensation, which will rarely strike the same place twice.
In addition to being caused by certain medical conditions, chronic parasthesia can also be caused by accident during medical procedures, and in some cases it is a common side effect. Dentists in particular notice temporary changes in sensation among their patients after procedures such as root canals. Patients should always report changes in sensation to a doctor, even if they are expected, so that the doctor can stay up to date on the patient's condition.
People who experience persistent and recurrent changes in sensation should consult a neurologist. The neurologist can determine the underlying cause and work with the patient to develop a treatment plan for the condition which is causing the issue. Over the course of treatment, the parasthesia should naturally resolve. In some cases, it may not be possible to treat the underlying condition, in which case various techniques can be used to help the patient cope with the parasthesia.