A numb or tingling sensation in the tongue, medically termed paresthesia, originates from a disruption of nerve signals. The tongue is densely packed with nerve endings that transmit sensation and taste to the brain, making it highly sensitive. When this communication system is interrupted by irritation or damage, the resulting feeling is often a pins-and-needles sensation or a complete loss of feeling. The reasons for this nerve signal interference vary widely, ranging from minor, temporary issues to chronic, underlying medical conditions.
Common Localized and Temporary Triggers
The most frequent causes of tongue numbness are often benign and result from direct irritation or localized trauma. Accidental biting of the tongue, for example, can cause temporary nerve bruising that manifests as short-lived paresthesia. Exposure to hot foods or liquids can cause minor burns that overwhelm the nerve endings, leading to a transient loss of sensation until the tissue recovers.
Chemical irritants, such as those found in acidic or spicy foods, can temporarily irritate the sensory nerves in the tongue. A common scenario involves dental procedures, particularly the lingering effects of local anesthetic used for fillings or extractions. The anesthetic temporarily blocks nerve transmission, and the numbness may persist for several hours as the medication wears off.
The mechanical process of a tooth extraction, especially for wisdom teeth, can cause localized trauma to the lingual nerve, which runs close to the jawbone. While most nerve irritation from dental work resolves spontaneously over a few weeks as the nerve heals, persistent numbness warrants further evaluation. Transient allergic reactions to certain foods or dental products, like mouthwash or toothpaste, can trigger immediate, brief tingling and swelling.
Nutritional Deficiencies and Systemic Imbalances
Beyond local irritation, tongue numbness can signal systemic imbalances affecting the peripheral nervous system. A deficiency in Vitamin B12, also known as cobalamin, is a dietary cause because this vitamin maintains the myelin sheath. Myelin is the fatty substance that insulates nerve fibers; its deterioration due to B12 deficiency impairs nerve signal conduction, resulting in neuropathic symptoms like tingling or numbness.
Folate (Vitamin B9) works closely with Vitamin B12, and a deficiency in either can disrupt nerve function and lead to similar symptoms. When these vitamins are chronically insufficient, the nerve damage can become permanent if not addressed through supplementation or dietary changes. Low levels of calcium in the blood (hypocalcemia) can also cause tingling sensations because calcium is directly involved in nerve impulse transmission.
Another temporary cause is anxiety-induced hyperventilation, which alters blood chemistry. Rapid, shallow breathing reduces the carbon dioxide concentration in the blood, causing a transient change in blood pH. This shift, known as respiratory alkalosis, increases nerve excitability, leading to the familiar tingling or pins-and-needles sensation, including in the tongue.
Neurological Conditions and Underlying Diseases
When tongue numbness is persistent, it may indicate a chronic condition affecting the central or peripheral nervous system. Peripheral neuropathy, nerve damage affecting nerves outside the brain and spinal cord, is a common cause, often linked to uncontrolled diabetes. High blood sugar levels over time can damage the small blood vessels supplying the nerves, leading to numbness and other sensory changes.
Acute neurological events like a stroke or a Transient Ischemic Attack (TIA) can present with sudden tongue numbness. These events occur when blood flow to a part of the brain is blocked; if the affected area controls sensation, the symptom is often sudden numbness on one side of the tongue or face. Autoimmune disorders, such as Multiple Sclerosis (MS), can also cause this symptom through demyelination. In MS, the immune system attacks the myelin sheath of nerves in the brain and spinal cord, potentially affecting cranial nerves responsible for tongue sensation.
Medications can induce this symptom as a systemic side effect, with certain chemotherapy or anti-seizure drugs sometimes causing general nerve irritation. This medication-related paresthesia typically involves a diffuse tingling sensation, rather than numbness localized to a single spot. Hypothyroidism, where the thyroid gland does not produce enough hormones, is another underlying disease that can cause nerve issues leading to numbness.
When to Seek Immediate Medical Attention
Sudden onset of tongue numbness, especially when accompanied by other symptoms, can signal a medical emergency requiring immediate attention. The primary concern is an acute neurological event like a stroke or TIA, where rapid treatment is necessary to prevent permanent damage.
Call emergency services if the numbness is accompanied by sudden weakness or paralysis affecting one side of the face, arm, or leg. Other warning signs include sudden difficulty speaking or understanding speech, confusion, or a severe headache without a known cause. Even if the numbness is brief and resolves quickly, an urgent medical assessment is necessary to prevent a future, debilitating event.