A burning sensation in the mouth, clinically known as glossodynia or Burning Mouth Syndrome (BMS), is a recognized condition characterized by persistent pain without an apparent dental or medical cause. Since the emergence of the SARS-CoV-2 pandemic, medical observations have increasingly linked this uncomfortable sensation to the viral infection. Findings indicate that this symptom is a genuine manifestation of the illness, occurring during the acute phase or following recovery. This article explores the documentation of this oral symptom, its underlying biological mechanisms, and management strategies.
Documenting Burning Tongue as a COVID Symptom
Medical literature documents a range of oral issues associated with SARS-CoV-2 infection, often grouped under the term “COVID tongue.” Burning tongue sensation is one of these manifestations, formally identified in studies tracking confirmed infections. Prevalence rates vary, with some studies reporting approximately 5% of individuals experiencing the sensation, while others report rates as high as 15% in hospitalized patients.
This symptom is classified alongside other changes like tongue swelling, white patches, and ulcers, indicating the virus’s impact beyond the respiratory system. The frequency of burning mouth syndrome appears linked to the severity of the initial illness. For instance, the symptom is reported in about 4% of mild-to-moderate cases, but this rate increases significantly in more severe, hospitalized cases. This suggests that a robust inflammatory or immune response triggered by the infection may contribute to the development of oral pain.
Biological Mechanisms Causing Oral Pain
The burning tongue sensation arises from a complex interaction between the virus, the immune system, and the nervous system. One primary theory involves the direct targeting of oral tissues by SARS-CoV-2, which uses the Angiotensin-converting enzyme 2 (ACE2) receptor for cell entry. Since ACE2 receptors are present in epithelial cells throughout the oral cavity, including the tongue and salivary glands, viral binding can cause direct damage or trigger inflammation.
Systemic inflammation, characterized by the release of inflammatory molecules called cytokines, also contributes to the pain by altering the oral mucosal environment. Another significant mechanism is neuropathic pain, involving damage to sensory nerves, particularly the trigeminal nerve, which supplies the oral cavity. The virus or the immune response may damage these peripheral nerve endings, resulting in the misfiring of pain signals and causing a persistent burning sensation, even without visible lesions.
Dry mouth, or xerostomia, is a common secondary effect that can exacerbate the burning sensation. Reduced saliva production, possibly due to the virus affecting the salivary glands, removes the mouth’s natural protective and lubricating barrier. Furthermore, nutritional deficiencies induced by the illness, such as low zinc levels, have been observed in some patients, suggesting a potential cofactor in the development of this pain.
Strategies for Managing the Sensation
Managing the burning sensation requires a multi-faceted approach, starting with simple at-home measures. Maintaining adequate hydration is recommended, as drinking water helps combat dry mouth and provides temporary relief. Patients should also adjust their diet by avoiding known irritants like highly acidic foods, spicy dishes, and very hot beverages that can aggravate the sensitive oral mucosa.
Gentle oral hygiene practices are important to prevent further irritation. This includes using a soft-bristled toothbrush and selecting alcohol-free oral hygiene products, as alcohol can be drying. Medical interventions often focus on managing the underlying neuropathic component of the pain.
A healthcare provider may recommend specific topical agents, such as mouth rinses containing low concentrations of capsaicin, to desensitize nerve fibers. For severe and persistent pain, systemic medications typically used for neuropathic pain, like low-dose tricyclic antidepressants or certain anticonvulsants, may be prescribed. Consulting a dentist or physician is crucial for an accurate diagnosis and personalized treatment, especially since the sensation can sometimes indicate a secondary issue like oral thrush.
Timeline for Symptom Resolution
The duration of the burning tongue symptom varies significantly depending on the infection’s severity and the mechanism involved. In many cases, oral symptoms resolve spontaneously as the patient recovers from the acute phase. For those experiencing the sensation during the initial illness, it often disappears within a few days or weeks following the resolution of other COVID-19 symptoms.
However, the symptom may persist in a subset of patients, classifying it as a potential manifestation of Long COVID. In these instances, the burning mouth syndrome can last for months after the initial infection, requiring long-term management. This persistent oral pain is often attributed to chronic neuropathic changes that linger after the virus has cleared. The persistence of the sensation for longer than three months indicates the condition may require specialized treatment focused on nerve pain modulation.