Numbness in the tongue, medically termed paresthesia, describes an altered sensation such as tingling, prickling, or a partial to complete loss of feeling. This sensation can be unsettling, particularly when it affects one side of the tongue, like the left. Understanding the possible reasons behind this localized numbness can help alleviate concern and guide appropriate action.
The Sensation of Numbness
The tongue is richly supplied with nerves that transmit a variety of sensory signals to the brain. The lingual nerve, a branch of the trigeminal nerve, plays a primary role in conveying general sensations such as touch, temperature, and pain from the front two-thirds of the tongue to the brain. This nerve also carries fibers from the facial nerve (chorda tympani) responsible for taste perception in the same area.
When these nerves are disrupted or damaged, or if the brain’s interpretation of their signals is impaired, numbness or an altered feeling can result. This disruption can occur due to compression, irritation, or direct injury to the nerve pathways. The tongue’s involvement in essential functions like taste, speech, and swallowing makes any sensory change in this area particularly noticeable and impactful.
Temporary Reasons for Tongue Numbness
Localized tongue numbness, especially on one side, often stems from temporary and benign causes. Dental procedures are a common reason, as local anesthesia used for extractions, fillings, or root canals can temporarily numb the tongue. This effect typically resolves within a few hours, though more invasive procedures like wisdom tooth removal might cause numbness for 8 to 9 hours if the lingual nerve is irritated or traumatized during the process.
Minor trauma or injury can also lead to transient numbness. This includes accidentally biting the tongue, experiencing burns from hot food or drinks, or irritation from sharp foods. These incidents can cause localized swelling or nerve irritation, resulting in a temporary decrease in sensation as the tissue heals.
Certain foods and drinks can induce a temporary tingling or numbing sensation. Extremely hot, cold, or spicy items can irritate the tongue’s sensory receptors. Specific ingredients, like the compounds found in Szechuan peppercorns, are known to cause a distinct tingling and numbing effect by activating certain nerve channels.
Mild allergic reactions can manifest as localized tingling or swelling of the tongue after exposure to certain foods or substances. This sensation is usually part of oral allergy syndrome, where the immune system reacts to proteins in raw fruits, vegetables, or nuts that are similar to pollen allergens. These temporary reactions typically subside once the allergen is no longer present.
Medical Conditions Causing Tongue Numbness
While many instances of tongue numbness are temporary, persistent or recurring numbness, particularly on one side, can indicate an underlying medical condition. Neurological conditions are a significant concern, with stroke or transient ischemic attack (TIA) being among the most serious. Sudden onset numbness, especially if accompanied by facial droop, arm weakness, difficulty speaking, vision changes, or a severe headache, can signal a stroke. Numbness in the tongue, particularly at the tip, can occur if a stroke affects the thalamus, a brain region involved in sensory processing.
Other neurological conditions can also present with tongue numbness. Multiple Sclerosis (MS), an autoimmune disorder affecting the central nervous system, can cause numbness and tingling in various body parts, including the tongue, due to damage to nerve myelin. This can lead to difficulties with speech, chewing, and swallowing. Migraine with aura can sometimes include neurological symptoms like numbness or tingling in the tongue, face, or hands before or during the headache phase.
Nutritional deficiencies can impact nerve health and sensation. A deficiency in vitamin B12, for instance, is known to cause nerve damage (neuropathy) that can result in numbness or tingling, often in the hands and feet, but also affecting the tongue. Other symptoms of vitamin B12 deficiency may include fatigue, weakness, a sore tongue, and cognitive issues.
Severe allergic reactions, such as anaphylaxis, can cause rapid swelling and numbness of the tongue and throat. These reactions are often accompanied by difficulty breathing, hives, a sudden drop in blood pressure, and dizziness, requiring immediate medical attention. Certain medications can also list paresthesia, including tongue numbness, as a potential side effect.
When to Consult a Healthcare Professional
Knowing when to seek medical attention for tongue numbness is important for ensuring timely and appropriate care. Immediate emergency medical attention is necessary if tongue numbness appears suddenly, especially if it is accompanied by other concerning symptoms. These include facial drooping, weakness or numbness in an arm or leg, trouble speaking or understanding speech, confusion, vision changes, or a severe headache. These symptom combinations can indicate a stroke or TIA, requiring urgent assessment.
A visit to a healthcare professional is advisable if tongue numbness is persistent, worsening, spreading, or accompanied by other non-emergency but concerning symptoms. This includes significant pain, swelling, difficulty swallowing, unexplained weight loss, or if the numbness interferes with daily activities. Prolonged numbness after dental work, particularly if it lasts more than a few days to weeks, also warrants follow-up with a dentist or oral surgeon.
For mild, temporary numbness with a clear, benign cause, such as a recent tongue bite or minor burn, monitoring at home is often sufficient. If the sensation resolves on its own within a short period, medical intervention may not be necessary. However, if there is any doubt about the cause or if symptoms persist, consulting a doctor can provide clarity and peace of mind.