Paresthesia is a term that describes a burning or prickling—“pins and needles”—sensation in the body. Paresthesia has also been described as tingling, numbness, the sensation of crawling skin, or an itching sensation. This is most common in the hands, arms, legs, and feet, although paresthesia can be felt in other parts of the body as well. The sensation can occur at any time without a warning and is generally not painful.
Types and Causes of Paresthesia
There are two types of paresthesia: (1) acute or temporary, and (2) chronic. In temporary paresthesia, the most common form is from an acutely compressed nerve. Falling asleep with an arm draped over the back of a chair may result in a condition known as “Saturday night palsy,” which is caused by continual nerve compression by the prolonged pressure of the chair. When the person wakes, the muscles in the arm may be weakened, painful, and experience “pins and needles” as the compression begins to heal. Another possible nontraumatic injury may occur when a patient wakens from a surgical procedure to find the table edges or surfaces produced a slight compression injury known as “intraoperative positioning injuries.” In fact, the feeling of numbness and tingling when a person falls asleep on his or her arm, or sits with legs crossed for too long, are some of the early symptoms of acute nerve compression. In the majority of cases, as soon as the pressure is relieved from the compressed nerve, the sensation begins to go away.
In chronic paresthesia, there is usually an underlying disease that is the cause or traumatic damage to a nerve, such as a severe compression injury. Chronic paresthesia can be associated with nerve damage occurring over a period of time. Compression of a nerve may be the direct result of a physical condition, such as being bed-bound for an extended period of time, or it may be the result of a disease or disorder. Included within this category are conditions such as (1) degenerative disc disease affecting the spinal cord; (2) carpal tunnel syndrome (compression of the nerves of the wrist), radial tunnel syndrome (compression of the radial nerve in the arm that serves the muscles on the side of the thumb), and cubital tunnel syndrome (compression of the ulnar nerve in the arm, also called the “funny bone”), all of which affect the upper extremities; (3) “cyclist’s palsy,” a condition frequently experienced by cyclists affecting their hands from constant pressure on the handlebars; (4) pressure exerted on the nerves by the presence of inflammation or a growth such as a tumor; (5) multiple sclerosis; and (6) stroke or transient ischemic attacks (mini-strokes).
Chronic paresthesia may result in a condition known as peripheral neuropathy. Peripheral nerves relay sensory information to the central nervous system such as a feeling of burn on touching a hot pan, pain when one receives a paper cut, or pressure when pushing open a door, for example. Any form of damage to the peripheral nerves in the peripheral nervous system will have detrimental effects on these crucial connections. Similar to a bad telephone line or poor Internet connection, the presence of peripheral neuropathy may alter, interrupt, or impede the messages passed between the peripheral and central nervous systems.
Because every peripheral nerve in different regions of the body possesses a highly specialized function that is specific to its location, peripheral neuropathy may produce an enormous array of varying symptoms. Patients may experience a variety of sensations ranging from mild to severe, which include temporary numbness, tingling, pricking, sensitivity to touch, muscle weakness, or outright discomfort. Some of the more extreme symptoms include burning pain (especially at night), muscle wasting, paralysis, or organ or gland dysfunction. People may be unable to digest food easily, maintain safe levels of blood pressure, sweat normally, or experience normal sexual function. In the most extreme cases, breathing may become difficult or organ failure may occur.
For acute or temporary paresthesia, if the source of pressure is relieved, the blood will return to the region and the sensation will begin to dissipate. Nerves will begin to heal, provided the cell bodies are not completely destroyed, scarred, or damaged too severely, and functionality will return. The blood—nerve barrier will be restored and the symptoms of the compression injury will subside. In chronic paresthesia, treating the underlying cause needs to be addressed for best results.
Jennifer L. Hellier
See also: Central Nervous System; Free Nerve Endings; Nerves; Nociception
National Institute of Neurological Disorders and Stroke (NINDS). (2015). NINDS paresthesia information page. Retrieved from http://www.ninds.nih.gov/disorders/paresthesia/paresthesia.htm
National Institute of Neurological Disorders and Stroke (NINDS). (2016). NINDS peripheral neuropathy information page. Retrieved from http://www.ninds.nih.gov/disorders/peripheralneuropathy/peripheralneuropathy.htm