Understanding the "Pins and Needles" Feeling
A tingling or numb feeling is a condition called paresthesia. It’s a sign that a nerve
is irritated and sending extra signals. Think of that pins and needles feeling as
a traffic jam in your nervous system.
When traffic is running smoothly, tiny electrical impulses move along the nerves that
run from your spine to your arms and legs. These sensations then move up the spinal
cord to the brain.
But if constant pressure is placed on a nerve, it causes a roadblock. This prevents
the nervous system from carrying the electrical impulses that normally transmit feeling.
This often leads to a loss of feeling, or numbness. Sometimes the irritation causes
signals when there should be none. This causes a tingling feeling (paresthesia). This
can be uncomfortable or painful.
Cause of "pins and needles"
Paresthesia can result from many different causes. It is often caused by nerve, spinal
cord, or brain irritation or damage. It can be temporary (reversible) or permanent.
While the nerve is squeezed, so are the arteries that feed blood to the nerve. The
nerve can't work for long without a steady supply of oxygen and glucose. Anything
that gets in the way of the nerve’s ability to send signals or with its blood supply
causes a limb to “fall asleep.” For example, people in wheelchairs who sit for long
periods of time are more likely to have nerve “traffic jams.”
When the blockage is removed, the nerve cells start waking up as they start getting
impulses again. You may start to have an uncomfortable pins and needles feeling. The
nervous system tends to become hyperactive as nerves regain normal function.
The nerve structures, as they recover, tend to be irritable for a period of time.
That’s because the nerves are firing spontaneously. Most of the time, the pins and
needles feeling is a good sign. It's a short-term phase that means nerves are coming
back to life.
Paresthesia can be felt in people who have an implanted spinal cord or peripheral
nerve stimulator.
When to worry
Most often, pins and needles is just an odd but harmless feeling that we have from
time to time. But it can also be more serious. In some cases, a nerve may be seriously
injured, perhaps in an accident. Then the nerve may get stuck in a pins and needles
stage. And you may have constant pain. A good example is carpal tunnel syndrome or
diabetic neuropathy. In these instances, the pins and needles feeling can be a danger
signal.
Paresthesia that happens with other symptoms may also mean there is an underlying
condition. People who have this happen very often may have an underlying problem with
their nerves. If these symptoms last for a long time or are linked to weakness, talk
with your healthcare provider. If paresthesia occurs suddenly and is linked to slurred
speech, facial drooping, or weakness, get medical care right away.