“COVID tongue” is a mysterious collection of signs and symptoms associated with the tongue and the rest of the oral cavity due to COVID-19 infection.
Symptoms include tongue swelling, inflammation, ulcers, and loss or change in the sense of taste. Its underlying causes are not well understood; hypotheses include viral damage, an overactive immune response, thrombosis, and oral thrush triggered by the COVID-19 virus or medication side effects.
Healthcare professionals (HCPs) should treat COVID-19-associated oral lesions on a case-by-case basis, focusing on symptom management including oral hygiene instructions, chlorhexidine gargles, anti-inflammatory medications, antifungals, and antiviral medications.
“COVID tongue,” an enigmatic yet increasingly recognized presentation of the COVID-19 infection, has piqued the interest of HCPs worldwide.
As the oral cavity remains a largely uncharted territory in the study of COVID-19, HCPs have had to devise strategies to treat COVID tongue, including anti-inflammatory and antiviral medications, chlorhexidine gargles, and antifungals, and management of its symptoms.
Origins of COVID tongue
The term COVID tongue first came into use in 2021 when British professor of genetic epidemiology Tim Spector, MD, tweeted about the prevalence of tongue changes like white patches, erosions, and ulcers among COVID-19 patients.
This information was gleaned from a study published by Zoe Health that began tracking COVID-19 symptoms in March 2020. Soon after, the term became commonly used.
The precise incidence of COVID-19-associated lingual lesions remains uncertain.
A study from 2021 published in Actas Dermo-Sifiliográficas found that up to 11.5% of hospitalized COVID-19 patients exhibited such symptoms.
As more data become available through ongoing global research efforts, the true prevalence of this phenomenon may be better characterized.
Signs and symptoms associated with COVID tongue cited by the Zoe Health report include:
Tongue swelling (macroglossia)
Inflammation of the tongue (glossitis)
Inflammation of lingual papillae (lingual papillitis)
Loss of lingual papillae creating smooth, red, patchy surfaces on the tongue (geographic tongue)
Aphthous ulcers and cold sores
Black hairy tongue
Petechial and hemorrhagic spots
Loss or alteration of gustatory perception (ageusia and dysgeusia)
Dryness of tongue
Although prevalent in COVID-19 patients, these symptoms may arise from various etiologies—from viral, bacterial, or fungal infections to poor oral hygiene and the use of antibiotics.
Due to this ambiguity, the CDC does not include tongue lesions in its comprehensive catalog of symptoms associated with COVID-19.
The underlying pathogenesis of COVID-related tongue symptoms remains largely obscure, with multiple hypotheses being put forth.
Some experts believe that the abundance of ACE2 receptors in the tongue may facilitate viral entry and elicit an inflammatory response, as reported in research published by Oral Surgery Oral Medicine Oral Pathology Oral Radiology. The oral cavity—specifically the tongue and oral mucosa—possesses a high density of ACE2 receptors, the key point of entry for the COVID-19 virus.
The virus may target these receptors and cause a cascade of events leading to swelling and inflammation of the tongue and oral mucosa. It also may cause disruptions in the salivary glands, resulting in a dry tongue.
Investigators publishing in Oral and Maxillofacial Surgery proposed that peri-vascular and peri-lymphocytic infiltration, due to overactive immune response, may account for the macroglossia in COVID tongue.
Research published in The American Journal of Surgical Pathology suggested that thrombosis may be the underlying cause. Vessel damage in the tongue triggers thrombotic events. This thrombi-induced vessel damage can lead to vascular lesions and ulcers on the tongue.
Changes in the oral microbial landscape, dry mouth, and prolonged immobility of the tongue in intubated patients are considered potential contributors.
A more succinct explanation is that the effects of COVID-19—and of the medications used in its treatment—on the immune system may render it more susceptible to secondary fungal and viral infections.
COVID tongue may also result from oral thrush caused by the fungus Candida albicans.
Another such example of secondary infection is the herpes simplex virus type 1-induced cold sores seen over the tongue in COVID-19 patients.
However, these tongue complications may be nothing but a coincidence. Stress and inadequate oral care—which have been prevalent amidst the COVID-19 pandemic—have been shown to aggravate these symptoms.
There is no standard treatment regimen for COVID-19-associated lingual lesions.
Treatment for COVID tongue, if it is a direct symptom of the virus, primarily focuses on managing symptoms.
Here are some options for addressing various tongue complications:
Macroglossia and glossitis are treated with anti-inflammatory or pain-relieving mouth rinse and over-the-counter anti-inflammatory medications. Macroglossia may cause airway obstruction, constituting a medical emergency. This warrants the need for systemic corticosteroids, NSAIDs like aceclofenac and ibuprofen, or immediate decompression therapy.
Lingual papillitis and patchy loss of papilla may be caused by candida glossitis. It is treated with antifungal medications like clotrimazole mouth paste and oral antifungals.
Tongue pain is managed with non-steroidal anti-inflammatory drugs (NSAIDs), and lignocaine gel or spray.
Aphthous ulcers and cold sores are usually self-resolving. Chlorhexidine gargles, povidone-iodine gargles, oral antiviral, and low-level laser therapy might be required in severe cases.
Black hairy tongue—or hyperkeratosis—caused by poor oral hygiene, can be treated with good oral hygiene, antifungal medications, chlorhexidine mouthwashes, or topical retinoids.
Dry mouth can be alleviated by advising the patient to stay hydrated and avoid caffeinated foods and beverages. Some patients may require artificial saliva.
Understanding of the COVID tongue is based on limited data, and further research is needed to fully unravel the intricacies of this unusual manifestation of the virus, as suggested by the authors of research published in the Journal of Oral Medicine and Oral Surgery.
Nonetheless, HCPs should remain vigilant for this possible symptom, as early detection and management of COVID-19 cases are paramount. Patients who suspect they may have COVID tongue should seek medical attention without delay.
What this means for you
When patients present with symptoms of COVID tongue, physicians should attend to those symptoms to alleviate their suffering as further research is done on the disorder. Treat the symptoms based on the patient’s unique case, emphasizing oral hygiene, antifungals, and anti-inflammatory and antiviral medications.
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