The sensation of a burning tongue, medically termed glossodynia or glossopyrosis, is a common and often distressing symptom. This feeling is frequently described as a scalding, tingling, or numbness that can occur on the tip, sides, or roof of the mouth. The causes range from direct physical encounters to complex underlying medical and neurological conditions.
Immediate Causes and Direct Irritants
The most straightforward explanation for a burning tongue involves a direct physical or chemical injury to the delicate oral tissue. Thermal trauma, from consuming food or beverages that are too hot, is a common cause, resulting in a minor burn on the tongue’s surface. While this pain is acute and subsides as the tissue heals, repeated exposure can maintain sensitivity.
Chemical irritants in certain foods and products can also trigger this sensation. Highly acidic foods, such as citrus fruits, can erode the protective mucosal layer, leading to irritation. Similarly, the compound capsaicin in spicy foods activates the same pain receptors that respond to heat, creating the characteristic burning feeling.
Contact allergies or sensitivities to ingredients in oral care products are another frequent trigger. The surfactant sodium lauryl sulfate (SLS), a foaming agent found in many toothpastes, is known to be an irritant. SLS can strip away the mouth’s protective lipid layer, leaving the oral lining vulnerable to inflammation and a burning sensation. This often resolves upon switching to an SLS-free product.
Physical trauma, or mechanical irritation, can also cause localized burning. This includes chronic rubbing from sharp edges on broken or chipped teeth, ill-fitting dentures, or new dental restorations that have not been properly smoothed. Even habitual behaviors like excessive tongue thrusting or constantly biting the tongue can lead to persistent soreness.
Systemic Conditions and Nutrient Deficiencies
A persistent burning tongue sensation often signals an underlying physiological issue. One common internal cause is Gastroesophageal Reflux Disease (GERD), where stomach acid moves back up into the esophagus and can eventually reach the mouth. This highly corrosive acid can alter the oral microbiome and directly irritate the tongue’s surface, leading to a chronic burning feeling.
Oral infections, particularly oral candidiasis (thrush), can lead to a burning sensation. This fungal infection is caused by an overgrowth of the Candida yeast, often manifesting as white patches, or a red and smooth tongue. The infection disrupts the normal oral environment, causing significant discomfort.
A lack of certain micronutrients is frequently implicated because these elements are necessary for maintaining healthy mucosal tissue. Deficiencies in B vitamins (B1, B2, B6, and B12) can lead to atrophic glossitis, where the tongue becomes smooth and painful. Similarly, insufficient levels of iron and zinc, crucial for cell regeneration, have been associated with oral burning.
Dry mouth, or xerostomia, occurs when the salivary glands do not produce enough saliva. Saliva normally acts as a natural buffer against irritants and aids in tissue repair. The reduced moisture increases friction and sensitivity, creating a raw, burning feeling. Systemic endocrine disorders, such as diabetes or hypothyroidism, can also contribute to the symptom, either through associated nerve changes or by making the patient more susceptible to infections like thrush.
Neuropathic Pain and Chronic Syndromes
When the burning sensation is persistent and no local or systemic cause can be identified, the symptom often falls under the category of neuropathic pain. Burning Mouth Syndrome (BMS) is a chronic pain disorder characterized by a burning, scalding, or tingling sensation lasting at least four to six months. In primary BMS, the pain is considered idiopathic, meaning it has no identifiable physical cause, and is thought to be related to dysfunction in the peripheral nerves that control pain and taste.
The pain from primary BMS is typically bilateral, affecting both sides of the tongue, and often worsens as the day progresses. Individuals with this syndrome may also experience a metallic or bitter taste, along with a subjective feeling of dry mouth, even if saliva production is normal. This chronic condition is most commonly observed in middle-aged and older women, especially during the perimenopausal or postmenopausal period, suggesting a hormonal link.
A number of medications can induce a burning sensation as a direct side effect, a condition sometimes referred to as secondary BMS. A notable class of drugs linked to this symptom is Angiotensin-Converting Enzyme (ACE) inhibitors, commonly prescribed for high blood pressure. Discontinuing the medication often leads to an improvement in symptoms within a few weeks.
In less common instances, the burning pain can be a sign of underlying nerve damage, or peripheral neuropathy, affecting the sensory nerves of the oral cavity. This involves damage to the nerves that transmit pain signals, leading to the misinterpretation of normal sensations as a burning discomfort. The complexity of these neurological mechanisms often requires specialized diagnostic evaluation.
Diagnosis and Management Options
Addressing a burning tongue requires a thorough and systematic approach to identify the specific underlying cause. A healthcare provider will typically begin with a detailed medical history and a physical examination to rule out visible lesions or signs of infection. If a systemic cause is suspected, diagnostic procedures often include blood tests to check for nutritional deficiencies, as well as tests for conditions like diabetes or thyroid problems.
If an allergy is suspected, patch testing or a trial of avoiding common irritants like SLS may be recommended. Management is directly targeted at the identified cause: antifungal medication for fungal infections, appropriate supplements for nutritional deficiencies, or adjustment/replacement for ill-fitting dental appliances.
For those diagnosed with primary Burning Mouth Syndrome, where no underlying cause is found, treatment focuses on managing the neuropathic pain. This may involve nerve pain medications or topical agents. Lifestyle adjustments are generally recommended, including avoiding known oral irritants like tobacco, spicy foods, and highly acidic drinks, and maintaining good hydration by sipping water or sucking on ice chips throughout the day.