Usually, no, but it can be. Most cases of that tingling sensation, which some lay people incorrectly call “numbness,” occur when a foot or hand “falls asleep,” said Dr. Ahmet Hoke, director of the neuromuscular division of neurology at Johns Hopkins School of Medicine.
If you sit on your feet, for example, that puts so much pressure on feet nerves that they temporarily become electrically unstable, sending off impulses to the brain when they shouldn’t. Typically, this feeling goes away within minutes of changing position. Carpal tunnel syndrome, in which nerves in the wrist are compressed, can produce longer-lasting tingling sensations. And an extreme example of pins and needles is “Saturday night palsy,” when a person becomes drunk and sleeps so heavily in one position that it can take weeks for crushed nerves to recover.
But a pins and needles feeling “is serious when there’s no good explanation for why it just happened, when it lasts longer than a few minutes or when it’s distributed all over the body in a way that wouldn’t make sense from some kind of mechanical injury,” said Dr. Lee Schwamm, vice chairman of the department of neurology at Massachusetts General Hospital.
A pins and needles sensation that can’t be explained and doesn’t resolve quickly may be a sign of one of the 100-plus types of peripheral neuropathy, in which nerves in the limbs are damaged. .
A tingling sensation in the leg can also be a sign of damage or pressure on the sciatic nerve, which runs from the lower back down the leg, or from a slipped disc in the spine. Numbness and tingling in a large region of the body, such as from the waist down, can also be a sign of serious inflammation in the spinal cord; and numbness or tingling, especially if accompanied by weakness, can be a sign of stroke if it occurs suddenly and on only one side of the body.
Bottom line: If the pins and needles go away, not to worry. If it persists, call a doctor.