What Causes the Pins & Needles Feeling?

People often feel the "pins and needles" feelings in the arms, legs or other parts of their body. This numbness, called paresthesia, is a condition that has many different potential causes. Some of these causes aren't very serious, but persistent "pins and needles" may be the symptom of a much more serious condition.

Definition

• Paresthesia is caused when the nerve cells carrying sensation to your brain are disturbed in one way or another. This disturbance can occur anywhere along the nervous system connecting the body part. The brain stops receiving complete information from the nerves, creating numbness with "pins and needles." The "pins and needles" are imperfect perceptions of sensation. Essentially, they are brief flashes of sensation that disappear quickly because of the disturbance in the nerves.

Ischemia

• The most common cause of pins and needles is ischemia. Ischemia is when the body part "falls asleep" because the blood supply is cut off. This occurs when people sleep on their arm, sit with their legs crossed or otherwise cut off the supply of blood. This condition is not serious and usually goes away after the blood flow returns to the body part.

Compression

• Chronic nerve compression can also create paresthesia. Nerve compression can include pinched nerves, spinal arthritis, carpal tunnel syndrome or swelling of the body. Some of these conditions may be reversed. For example, pinched nerves can be repaired through careful spinal cord adjustments, if the nerve is pinched in the back. Spinal arthritis can only be treated, not reversed.

Metabolic Disturbances

• When the metabolic process is disturbed, it may cause tingling. These conditions include diabetes, hypothyroidism, malnutrition and even alcoholism. The metabolic process helps provide nutrition for the body and keeps it operating smoothly and efficiently. A poorly maintained metabolic process can lead to improperly operating nerves or simply a lack of blood flow to the nerves.

Trauma

• Severe trauma can also cause paresthesia. These traumatic events include any that cause the nerves to be crushed, severed or pulled harshly. Traumatic damage to the nerves can rarely be completely healed, which may lead to lifelong paresthesia or even paralysis.

Swelling

• Swelling can cause the tissue around the nerves to squeeze the nerve and disrupt the flow of neurons. It may also squeeze the blood vessels, leading to ischemia. Swelling can't usually damage the nerves, so this paresthesia usually goes away when the swelling goes down.

Poison

• There are many poisons and toxins that can cause the tingling of paresthesia. Heavy metals such as arsenic, lead and mercury can cause disruption of neuron flow. Chemotherapy chemicals may also cause temporary paresthesia. Too much vitamin B6 may also cause disruption. If you suspect you have taken any of these toxins, go to a poison control center or hospital immediately.

Other Causes

• There are many other conditions that can affect neuron flow. Arthritis and lupus can cause pins and needles throughout wide areas of the body. Polyarteritis nodosa causes ischemia throughout the body by creating inflamed arteries.