Paresthesia

Paresthesia, also known aspins and needles, is an abnormal sensation of the skin (tingling, pricking, chilling, burning,numbness) with no apparent physical cause.Paresthesia may be transient or chronic, and may have many possible underlying causes.Paresthesias are usually painless and can occur anywhere on the body, but most commonly occur in the arms and legs.
The most familiar kind of paresthesia is the sensation known as "pins and needles" afterhaving a limb "fall asleep". A less well-known and uncommon paresthesia isformication, the sensation of insects crawling on the skin.
Paresthesias of the hands, feet, legs, and arms are common transient symptoms. The briefest electric shock type of paresthesia can be caused by tweaking theulnar nervenear the elbow; this phenomenon is colloquially known as bumping one's "funny bone". Similar brief shocks can be experienced when any other nerve is tweaked (e.g. a pinched neck nerve may cause a brief shock-like paresthesia toward the scalp). In the older age group, spinal column irregularities may tweak the spinal cord briefly when the head or back is turned, flexed, or extended into brief uncommon positions (Lhermitte's sign).
The most common everyday cause is temporary restriction of nerve impulses to an area of nerves, commonly caused by leaning or resting on parts of the body such as the legs (often followed by a pins and needles tingling sensation). Other causes include conditions such ashyperventilation syndromeandpanic attacks. A cold sore outside the mouth (not a canker sore inside the mouth) can be preceded by tingling due to activity of the causativeherpes simplex virus. Thevaricella zoster virus(shingles) also notably may cause recurring pain and tingling in skin or tissue along the distribution path of that nerve (most commonly in the skin, along adermatomepattern, but sometimes feeling like a headache, chest or abdominal pain, or pelvic pain).
Other common examples occur when sustained pressure has been applied over anerve, inhibiting or stimulating its function. Removing the pressure typically results in gradual relief of these paresthesias.Most pressure-induced paraesthesia results from awkward posture, such as engaging incross-legged sittingfor prolonged periods of time.
Reactive hyperaemia, which occurs when blood flow is restored after a period ofischemia, may be accompanied by paresthesia, e.g. when patients withRaynaud's diseaserewarm after a cold episode.
Cases of paresthesia have also been reported at varying frequencies followinganthrax,flu,HPVandCOVID-19vaccineintake.Benzodiazepinewithdrawal may also cause paresthesia, as the drug removal leaves theGABA receptorsstripped bare and possibly malformed.
Chronic paresthesia (Berger's paresthesia,Sinagesia,or Bernhardt paresthesia)indicates either a problem with the functioning ofneurons, or poorcirculation.
In the elderly, paresthesia is often the result of poor circulation in the limbs (such as inperipheral vascular disease), most often caused byatherosclerosis, the build-up of plaque within artery walls over decades, with eventualplaque ruptures, internal clots over the ruptures, and subsequent clot healing, but leaving behindnarrowingor closure of the artery openings, locally and/or in downstream smaller branches. Without a proper supply of blood and nutrients, nerve cells can no longer adequately send signals to the brain. Because of this, paresthesia can also be a symptom ofvitamin deficiencyor othermalnutrition, as well as metabolic disorders likediabetes,hypothyroidism, orhypoparathyroidism. It can also be a symptom ofmercury poisoning.
Irritation to the nerve can also come from inflammation to the tissue. Joint conditions such asrheumatoid arthritis,psoriatic arthritis, andcarpal tunnel syndromeare common sources of paresthesia. Nerves below the head may be compressed where chronic neck and spine problems exist, and can be caused by, among other things, muscle cramps that may be a result of clinical anxiety or excessive mental stress,bone disease, poor posture, unsafe heavy lifting practices, or physical trauma such aswhiplash.
Another cause of paresthesia may be direct damage to the nerves themselves, i.e.,neuropathy, which itself can stem frominjury, such as fromfrostbite; infections such asLyme disease; or may be indicative of a current neurological disorder. Neuropathy is also a side effect of some chemotherapies, such as in the case ofchemotherapy-induced peripheral neuropathy.Chronic paresthesia can sometimes be symptomatic of serious conditions, such as atransient ischemic attack; orautoimmune diseasessuch asmultiple sclerosis,complex regional pain syndrome, orlupus erythematosus.The use offluoroquinolonescan also cause paresthesia.Strokesurvivors and those withtraumatic brain injury(TBI) may experience paresthesia from damage to the central nervous system.
Acroparesthesia is severe pain in the extremities, and may be caused byFabry disease, a type ofsphingolipidosis.
It can also be a sign ofhypocalcemia.
Dental paresthesia is loss of sensation caused by maxillary or mandibular anesthetic administration before dental treatment.
Potential causes include trauma introduced to the nerve sheath during administration of the injection, hemorrhage about the sheath, more side-effect-prone types of anesthetic being used, or administration of anesthetic contaminated with alcohol or sterilizing solutions.
Other causes may include:
A nerve conduction study usually provides useful information for making a diagnosis. AnMRIor aCT scanis sometimes used to rule out certain causes stemming from central nervous system issues.
Medications offered can include theimmunosuppressantprednisone, intravenousgamma globulin(IVIG),anticonvulsantssuch asgabapentinortiagabine, orantiviralmedication, depending on the underlying cause.
In addition to treatment of the underlying disorder, palliative care can include the use of topical numbing creams, such aslidocaineorprilocaine.Ketaminehas also been successfully used, but is generally not approved by insurance. Careful consideration must be taken to apply only the necessary amount, as excess can contribute to these conditions. Otherwise, these products generally offer extremely effective, but short-lasting relief from these conditions.
Paresthesia caused by stroke may receive some temporary benefit from high doses ofbaclofenmultiple times a day.HIVpatients who self-medicate with cannabis report that it reduces their symptoms.
Paresthesia caused byshinglesis treated with appropriateantiviral medication.
The wordparesthesia(/ˌpærɪsˈθiːziə,-ʒə/; British Englishparaesthesia; plural paraesthesiae/-zii/or paraesthesias) comes from theGreekpara("beside",i.e., abnormal) andaisthesia("sensation").