Paresthesia

Paresthesia (or paraesthesia) is a sensation of the skin that may feel like numbness (hypoesthesia), tingling, pricking, chilling, or burning. It can be temporary or chronic and has many possible underlying causes. Similar brief shocks can be experienced when any other nerve is injured (e.g., a pinched neck nerve may cause a brief shock-like paresthesia toward the scalp). Spinal column irregularities may injure 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). Reactive hyperaemia, which occurs when blood flow is restored after a period of ischemia, may be accompanied by paresthesia too, e.g., when patients with Raynaud's disease rewarm after a cold episode. Other causes include conditions such as hyperventilation syndrome and panic attacks, in which paresthesias of the mouth, hands, and feet are common, transient symptoms. A cold sore outside the mouth (not a canker sore inside the mouth) can be preceded by tingling due to activity of the causative herpes simplex virus. The varicella zoster virus, which causes 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 a dermatome pattern, but sometimes feeling like a headache, chest or abdominal pain, or pelvic pain).

Paresthesias can also be a symptom of mercury poisoning. Seafood poisoning is also possible, e.g., ciguatera toxin is produced within dinoflagellate plankton, which when consumed by other sea animals and then by humans, can lead to perioral paresthesia and temperature-related dysesthesia.

Cases of paresthesia have also been reported at varying frequencies following anthrax, flu, HPV, and COVID-19 vaccine intake. Benzodiazepine withdrawal may also cause paresthesia, as the drug removal leaves the GABA receptors desensitized. Benzodiazepines (e.g., Xanax and Valium) can be prescribed to try to relax muscle spasms or suppress epileptic seizures.

Chronic

Chronic paresthesia (Berger's paresthesia, Sinagesia, or meralgia paresthetica) indicates either a problem with the functioning of neurons, or poor circulation. In the elderly, paresthesia is often the result of poor circulation in the limbs (such as in peripheral vascular disease), most often caused by atherosclerosis, the build-up of plaque within artery walls over decades, with eventual plaque ruptures, internal clots over the ruptures, and subsequent clot healing, but leaving behind narrowing or 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 of vitamin deficiency or other malnutrition, as well as metabolic disorders like diabetes, hypothyroidism, or hypoparathyroidism.

Irritation to the nerve can also come from inflammation to the tissue. Joint conditions such as rheumatoid arthritis, psoriatic arthritis, and carpal tunnel syndrome are 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 as whiplash. Chronic paresthesia can sometimes be symptomatic of serious conditions, such as a transient ischemic attack; or autoimmune diseases such as multiple sclerosis, complex regional pain syndrome, or lupus erythematosus. The use of fluoroquinolones can also cause paresthesia. Brainstem stroke survivors and those with traumatic brain injury (TBI) may experience paresthesia from damage to the central nervous system.

Acroparesthesia

Acroparesthesia is severe pain in the extremities, and may be caused by Fabry disease, a type of sphingolipidosis. It can also be a sign of hypocalcemia.

Dentistry

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.

Drugs

Anticonvulsant pharmaceutical drugs, such as topiramate, sultiame, or acetazolamide
Antidepressant discontinuation syndrome
Benzodiazepine withdrawal syndrome
Beta alanine
Dextromethorphan (recreational use)
Intravenous administering of strong pharmaceutical drugs acting on the central nervous system (CNS), mainly opiates, opioids, or other narcotics, especially in non-medical use (drug abuse)
Ketorolac
Lidocaine poisoning
Lomotil
Nitrous oxide, long-term exposure
Ritonavir

Other

Other causes may include:

Autonomous sensory meridian response ("ASMR")
Carpal tunnel syndrome
Cerebral amyloid angiopathy
Chiari malformation
Coeliac disease
Complex regional pain syndrome
Cubital tunnel syndrome
Decompression sickness
Dehydration
Erythromelalgia
Fabry disease
Fibromyalgia
Fluoroquinolone toxicity
Guillain–Barré syndrome (GBS)
Heavy metals
Herpes zoster
Hydroxy alpha sanshool, a component of Sichuan peppers
Hyperglycemia (high blood sugar)
Hyperkalemia
Hyperventilation
Hypocalcemia, and in turn:
Hypermagnesemia, a condition in which hypocalcemia itself is typically observed as a secondary symptom
Hypoglycemia (low blood sugar)
Hypothyroidism
Immunodeficiency, such as chronic inflammatory demyelinating polyneuropathy (CIDP)
Lupus erythematosus
Lyme disease
Magnesium deficiency, often as a result of long-term proton-pump inhibitor use
Menopause
Mercury poisoning
Migraines
Multiple sclerosis
Nerve compression syndrome
Obdormition
Oxygen toxicity, especially breathing oxygen under pressure, such as in scuba diving
Pyrethrum or pyrethroid pesticides
Post-polio syndrome
Rabies
Radiation poisoning
Sarcoidosis
Sciatica
Scorpion stings
Spinal disc herniation or injury
Spinal stenosis
Stinging nettles
Syringomyelia
Transverse myelitis
Variant Creutzfeldt–Jakob disease (AKA "mad cow disease")
Vitamin B5 deficiency
Vitamin B6 excess
Vitamin B12 deficiency

Diagnostics

A nerve conduction study usually provides useful information for making a diagnosis. An MRI or a CT scan is sometimes used to rule out certain causes stemming from central nervous system issues.

Treatment

Medications offered can include the immunosuppressant prednisone, intravenous gamma globulin (IVIG), anticonvulsants such as gabapentin or tiagabine, or antiviral medication, depending on the underlying cause.

In addition to treatment of the underlying disorder, palliative care can include the use of topical numbing creams, such as lidocaine or prilocaine. Ketamine has 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 of baclofen multiple times a day. HIV patients who self-medicate with cannabis report that it reduces their symptoms.

Paresthesia caused by shingles is treated with appropriate antiviral medication.

Etymology

The word paresthesia (; British English paraesthesia; plural paraesthesiae or paraesthesias) comes from the Greek para ("beside", i.e., 'abnormal') and aisthesia ("sensation").