The tongue is one of the most sensitive organs in the human body. In fact, it is often more sensitive than the skin to sensations such as pain perception, temperature sensitivity, pressure sensitivity, and the ability to distinguish different textures. In addition to these common sensations, it also possesses the unique ability to detect chemicals, a perception known as taste. The plethora of sensations that the tongue is capable of is due to the presence of different types of sensory nerve endings in the mucus membrane that lines the surface of this organ.
In certain conditions, the tongue starts to feel abnormal sensations that are not a part of its normal repertoire. These include feelings of numbness, burning, tingling, and pin-pricks. Such abnormal sensations, referred to as paresthesia, can occur not only in the tongue but also in other sensory organs. When a paresthesia affects the unique ability of the tongue to taste, it is known as dysgeusia or parageusia.
Other Signs and Symptoms
The most common symptoms seen in conditions of tongue paresthesia are:
- A feeling of numbness in the tongue
- A tingling sensation in the tongue, even though there is nothing on the tongue to cause that sensation.
- A burning sensation or a feeling of pins and needles pricking the tongue. This usually happens in the absence of any sensation-triggering substance on the tongue.
The presence of these abnormal sensations, mostly in the absence of any real causative substance on the tongue, is an indication of tongue paresthesia.
Causes of Tongue Numbness and Tingling
The sensations that we perceive from the tongue depend on the proper functioning of the sensory nerves that are present in this organ. These sensory nerves have a variety of specialized endings that are responsible for detecting whatever comes in contact with the tongue. For example, sensory nerves that sense pressure (called mechanoreceptors) have specialized nerve endings to sense the amount of pressure. Sensory nerves that sense hot or cold (called thermoreceptors) have specialized nerve endings to sense temperature changes.
Therefore the various types of sensory nerves are specialized to sense different types of stimuli. Upon detection of a particular stimuli, these sensory nerves relay that information to the brain, where the sense of specific perception is created. In cases of paresthesia, these sensory nerves either stop sensing (e.g, in case of numbness), start sending wrong messages in the absence of any stimuli (e.g., tingling, pins and needles sensation), or the brain erroneously interprets the signals from the sensory nerves.
Paresthesias can be caused by a variety of factors, as described below:
- Medication: There are some cases where paresthesia can be caused by some real rather than perceived stimuli. Medicines are one such class of causative factors. Tongue numbness or paresthesia can occur upon accidental ingestion of topical anesthetics, certain alcohols, narcotics, and prescription medicines. In some cases, tongue paresthesia such as tingling sensation could be due to side-effects of a particular drug. Most of these cases of tongue paresthesia are temporary and go away on their own. Exceptions include cases where permanent damage occurs to the nerves in the tongue and the paresthesias that ensue become long-term.
- Toxins: The most common toxins that cause tongue paresthesias such as tingling sensations or numbness come from seafood. A variety of fishes harbor toxins which affect the sensory nerves in the tongue. For example, barracudas, eels and sea bass contain ciguatera toxins that can lead to poisoning and tongue paresthesia. Eating spoilt fish that has not been stored properly can lead to tongue paresthesia and scromboid food poisoning.
Some of these fish toxins can even be lethal. For example, the lethal puffer fish toxins cause numbness and tingling sensations in the tongue and the lips when the fish is cooked by licensed and experienced chefs. However, in inexperienced hands, even a small dose of puffer fish toxin (called tetrodotoxin) can be lethal. Heavy metal poisoning can also be characterized by tingling sensations and numbness in the tongue and other parts of the body.
- Dental procedures: Anyone who has undergone a dental procedure that required the use of a local anesthetic would have experienced temporary sensations of numbness and tingling in the tongue, cheeks and the gums. These sensations usually wear off in a few hours. However, some dental procedures like root canal, tooth extraction and dental implants can accidently result in injury to the lingual nerve in the tongue and subsequently cause permanent tongue paresthesia or numbness.
- Trauma: As mentioned above, the main cause of tongue paresthesias is injury to the nerves and tissues of the tongue. Trauma due to a variety of causes can injure the nerves of the tongue and cause pain, numbness and tingling sensations. Examples range from factors causing mild and temporary cases of paresthesia (e.g., ingestion of very hot and very cold substances, acids and alkalies, aerated drinks) to factors that cause long term paresthesia sensations (e.g., radiation treatment in oral cancers, tongue piercings).
- Infections: Infections that can result in tongue paresthesias like tingling sensations include oral herpes (caused by Herpes simplex virus), shingles (caused by reactivation of the chickenpox virus), and oral thrush (caused by the fungi Candida).
- Nutritional abnormalities: Excessive intake or deficiency of certain micronutrients essential for the proper functioning of the nervous system can also lead to paresthesia in the tongue. An excess or deficiency of minerals such as calcium, potassium, and sodium leads to tingling sensations in the tongue. Deficiency of vitamin B12 also leads to tongue paresthesia with feelings of numbness and tingling.
Many other causes that affect the proper functioning of the nervous system also result in paresthesia in the tongue and other parts of the body. Examples include diseases such as multiple sclerosis, tumors in the brain or in other parts of the body, facial palsy, migraines, and hypothyroidism. Strokes can also lead to paresthesia in multiple parts of the body, including the tongue.
Treatment of Tongue Numbness and Tingling
Since tongue paresthesia can be caused by a multitude of different factors, the appropriate line of treatment can only be ascertained after identifying the cause of the abnormal sensations. In case of temporary paresthesia, there is little cause for concern since the symptoms go away on their own. However, other cases of tongue paresthesia could be due to serious underlying issues that warrant medical investigations by a doctor.