Paresthesia is a symptom that few people know the name of, but most experience at some point. It commonly manifests after a person sits cross-legged for too long or falls asleep on their arm and is usually called “pins and needles.” Paresthesia is generally a painless sensation that disappears quickly without any intervention. However, if it occurs regularly or for long periods, it may be a symptom of a serious condition. Consultation with a doctor can help to determine the underlying cause.
What is Paresthesia?
Medically, paresthesia is an abnormal sensation of the skin. These sensations can include tingling, pricking, chilling, burning, and numbness, and they usually occur spontaneously. Less common is formication, which feels like bugs crawling under the skin. Any body part can experience paresthesia, but is most common on the arms, legs, hands, and feet. The sensations may cause clumsiness, especially when felt in the legs and feet.
Chronic and Transient Paresthesia
Paresthesia is either chronic or transient. Transient paresthesia is a temporary condition, usually caused by a pinched nerve or prolonged pressure on a nerve through resting on it or poor posture. Paresthesia is defined as chronic when an individual experiences it for long periods or if it repeatedly occurs without any clear cause. Poor circulation is the most likely reason for chronic paresthesia, but can also indicate a problem with the nervous system.
Diagnosing the Cause of Paresthesia
When someone presents with paresthesia, doctors aim to discover the underlying cause of the symptom by requesting a detailed medical history and enquiring into hobbies or occupations that involve repetitive movements. Further tests may include a nerve conduction study, which measures how fast nerve impulses travel, and MRI or CT scans. Sometimes an ultrasound can help view nerve compression or damage in smaller parts of the body, such as the wrists.
Causes: Nerve Issues
The most common cause of paresthesia is nerve issues. Radiculopathy is the compression or inflammation of nerve roots. Any condition that puts pressure on the nerve can cause this, including herniated disks, carpal tunnel syndrome, and the inflamed joints associated with arthritis. Chronic nerve damage or neuropathy can also cause paresthesia. Traumatic brain injury commonly leads to neuropathy, as does stroke, frostbite, and repetitive movement injuries like tennis elbow.
Some viruses cause paresthesia. The varicella zoster virus (VZV) lives in the nerves and leads to shingles. Many people experience a tingling sensation two to four days before the rash associated with the disease appears. The herpes simplex virus, which causes cold sores, is in the same family as VZV and the tingling associated with an emerging cold sore is another example of paresthesia.
Some medications can cause paresthesia, including certain anticonvulsants and chemotherapy medications. Strong intravenous drugs such as opioids and narcotics can also cause the sensation, especially when used in non-medically. Withdrawal can also cause paresthesia; in particular, people withdrawing from benzodiazepines, a class of drugs used to treat anxiety, panic disorder, and insomnia, often experience tingling sensations. People exposed to certain poisons, including mercury, radiation, and some insecticides may also have paresthesia.
Causes: Serious Conditions
Paresthesia may be an early symptom of autoimmune diseases such as rheumatoid arthritis and nervous system conditions like multiple sclerosis. As paresthesia can be caused by poor circulation, it may also signify plaque build-up in the arteries. High blood sugar is a common cause of neuropathy, so diabetes can lead to the sensations, as well.
Other Possible Causes of Paresthesia
It is difficult to list all the possible causes of paresthesia, as it is so common. Previously unmentioned conditions that can trigger paresthesia include
- vitamin B5 or B12 deficiency
- magnesium deficiency
- decompression sickness
- celiac disease
- kidney, liver, or thyroid disease.
People can also experience paresthesia in the mouth after dental visits, due to contaminated anesthesia or the type of anesthesia the dentist used. It is also possible for dentists to cause damage to the nerve when injecting drugs.
Risk Factors for Paresthesia
In addition to having a condition that causes paresthesia, some common risk factors increase the likelihood a person will experience the sensation. Excess weight can place pressure on the nerves, making people with obesity and pregnant women higher risk demographics. Those on prolonged bed rest may also experience paresthesia when laying in one position compresses the nerves. People whose jobs or hobbies require repetitive movements, such as typing or swinging a golf club, are at greater risk. This is especially true for women, whose smaller frames make them more susceptible to carpal tunnel syndrome.
Treatment of Paresthesia
Most treatments for paresthesia concentrate on the underlying cause. Compressed nerves and repetitive strain injuries can benefit from braces and physical therapy to help take pressure off the nerves. Numbing creams can help, although they can exacerbate the condition if used excessively. Ibuprofen and steroid injections can decrease swelling that may contribute to paresthesia. Although no studies exist yet, some people report that cannabis helps relieve the sensation.