What Is 'COVID Tongue'?

Since the start of the COVID-19 pandemic, reports have surfaced of symptoms of COVID-19 related to your mouth. Features of "COVID tongue" include tongue discoloration, enlargement, mouth ulcers, and more.

The reports initially came from England where Tim Spector, a researcher at King’s College London, was tracking COVID-19 symptoms in British patients. He began noticing an increasing number of patients with tongue discoloration, enlargement, and other mouth problems.

Is this an indicator of COVID-19 infection? Verywell asked experts whether COVID tongue is real and how worried the public should be.

Is "COVID Tongue" Real?

Susannah Hills, MD, an airway surgeon and assistant professor of Otolaryngology at New York-Presbyterian/Columbia University, tells Verywell that she's not entirely convinced that COVID tongue is a real diagnostic sign.

“Tim Spector recently reported COVID tongue as a ‘thing’ but said it affects less than one in 100 people in their research database of COVID cases," says Hills. In an interview with USA Today, Spector said that one in five people will present with unofficial symptoms such as discolored or swollen tongues.

Hills says that in her mind, "it’s really difficult to make an association between a disease and a symptom that’s showing up that infrequently.”

Peter Gulick, DO, professor of medicine and infectious disease expert at Michigan State University College of Osteopathic Medicine, tells Verywell that he thinks it's still too early to tell if COVID tongue is real—but he does think it's possible.

Gulick points out that for safety reasons, healthcare providers reduced the number of exams they performed that require a patient to take their mask off.

“Maybe things weren’t seen because nobody did the exams, and maybe [patients] dismissed it as poor hygiene rather than looking at it specifically as a COVID issue,” Gulick says. “And if [doctors are] doing a lot of virtual screenings, then we never see the patient beyond the television monitor, so you can’t really see the mouth either.”

Studies Linking Mouth Problems to COVID

While research is ongoing, there have been numerous studies linking oral problems to the COVID-19 virus.

Studies from 2020 found oral symptoms in people with COVID-19 including tongue inflammation, mouth ulcers, and tongue discoloration. Tongue discoloration differed in patients with mild to moderate infections, who had a light red tongue with a white coating, while those with severe infections were associated with purple and yellow tongues.

A 2022 study published in BMC Oral Health suggested that stress experienced during the pandemic was a factor that led to geographic tongue and other oral problems. Still, a 2023 review published in Infection and Drug Resistance looked at earlier studies investigating COVID-related oral symptoms, but the researchers did not come to the conclusion that the symptoms were a direct result of infection.

Other commonly reported symptoms with earlier COVID-19 variants were loss of taste and smell. After Omicron became the dominant variant, these symptoms were less likely to occur.

However, researchers have found loss of taste from COVID-19 can be long-lasting and recovery can take months. A 2022 study published in PLoS One found that around 30% of people who experienced loss of taste from COVID-19 did not fully recover their sense of taste eight months after having COVID.

Possible Causes of COVID Mouth Problems

Research has not conclusively determined the cause of the oral problems linked to COVID-19. However, there are several mechanisms that could explain the link.

Brain and Nerve Effects

Hills suggests that since there is evidence of the COVID-19 virus affecting the brain, it could also potentially injure or hijack the nerves that control the tongue.

COVID-19 Treatments

There’s also a chance that COVID-19 treatments could be indirectly causing mouth problems. “For patients who aren’t able to eat or drink normally because of the illness, or for those who are in the hospital receiving breathing support or even requiring a breathing tube or a feeding tube, there could also be injury or irritation of the tongue tissues from trauma, dry air, or even nutritional deficits (like B12) from not being able to eat well," Hills says.

Dry Mouth

Gulick says that a COVID-19 infection in the salivary gland could decrease secretion in the mouth and cause dry mouth, also called xerostomia. Having a dry mouth, in turn, could prompt other oral issues that have also been linked to COVID-19, such as tooth decay and tooth loss.

The ACE2 receptors targeted by the COVID-19 virus are present in the lungs and several mouth areas, including the salivary glands. It is thought that the virus attacks and damages salivary gland cells, leading to impaired function, including decreased saliva production.

Thrush

Gulick also says that reports of "furry tongues" could be from steroids such as dexamethasone that cause an immunosuppressed state, which can make a person susceptible to oral thrush.

Other Viral Infections

COVID-19 increases inflammation, which may indirectly activate other viral infections such as the herpes simplex virus, which can cause mouth ulcers.

A case report published in June 2020 documented a similar scenario. One patient tested positive for COVID-19 and soon after experienced a series of conditions, including a herpes infection, oral thrush, and a geographic tongue.

Why Good Oral Health Matters

Your mouth is teeming with bacteria. Keeping it as clean as possible is essential to mitigate ulcer formation and any other potentially COVID-related inflammation. At the very least, if there was an acute inflammatory response, Gulick says that good oral health won’t make the problem any worse.

As doctors and researchers learn more about COVID tongue, there are some things that you can do. For one, stay abreast of any changes to your oral health and if you notice anything unusual, tell your healthcare provider.

If you think you have COVID-19, whether or not you have any mouth-related symptoms, the best thing you can do is get tested. “If it was me and I didn’t know why my mouth was like this, I would go and do a COVID test just to cover all the bases," Gulick says.

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.