It started with a weird tweet. Back in early 2021, Professor Tim Spector, an epidemiologist at King’s College London and the lead scientist behind the ZOE Health Study, noticed something strange. He was seeing an uptick in reports of people with "strange ulcers" and "furry tongues" following a positive PCR test. He called it covid tongue.
Suddenly, everyone was looking in the mirror.
Most of us know the classic symptoms: the cough that won't quit, the fever, and that weird loss of taste. But the mouth is often a mirror for what’s happening in the rest of the body. If your immune system is in a fistfight with a virus, it’s going to leave some marks. Covid tongue isn't a single "thing," really. It’s a catch-all term for several different oral issues that pop up when SARS-CoV-2 hitches a ride in your system.
So, what exactly is covid tongue?
Honestly, it’s a bit of a mess to define. Medical professionals generally use the term to describe inflammation of the tongue (glossitis) or changes in the surface of the mouth that appear alongside a COVID-19 infection.
You might see patches. You might see swelling.
Sometimes the tongue looks like a "geographic tongue," which is a fancy way of saying it has red, smooth patches surrounded by white borders that look like a map. Other people report a "hairy" or "furry" appearance. This happens because the tiny bumps on your tongue, called papillae, get inflamed. When they don't shed properly, they trap bacteria and food particles. It's gross, yeah, but it's basically just a sign that your body is distracted by a major viral invader.
The Science Behind the Swelling
Why the mouth? Think about ACE2 receptors. These are the "cellular doorways" that the virus uses to break into your cells. It turns out your tongue and the lining of your mouth are absolutely packed with these receptors.
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A study published in Nature Medicine by researchers from the National Institutes of Health (NIH) and the University of North Carolina at Chapel Hill confirmed that the salivary glands and the tissue in the mouth are actually primary sites for infection. This isn't just a side effect; the virus is literally setting up shop in your mouth. This explains why your saliva is such an effective way to test for the virus in the first place.
Warning Signs and Weird Textures
If you’re wondering if that spot on your tongue is related to the virus, there are a few specific things doctors look for.
- Macroglossia: This is a medical term for a swollen tongue. It can get so bad that you see teeth indentations along the edges.
- White Patches: These can look like oral thrush (a yeast infection). It’s common because the virus—and sometimes the steroids used to treat it—can mess with your mouth's natural microbiome.
- Aphthous Ulcers: Basically, nasty canker sores. They hurt. They're usually red and can appear on the tongue or the inside of the cheeks.
- The "Strawberry" Look: Intense redness and bumps that make the tongue look like the surface of a berry.
It's not just the tongue, though. Some patients report extreme dryness, known as xerostomia. Your mouth feels like a desert. This happens because the virus can infect the salivary glands directly, slowing down the production of spit. Without enough saliva, the pH balance of your mouth shifts, leading to more irritation and that "furry" feeling.
Is it common or just a "Long Covid" quirk?
Early on, it seemed rare. But as the ZOE study gathered more data from millions of users, it became clear that "odd" symptoms like covid tongue were appearing in up to 1 in 500 cases. That doesn’t sound like much until you realize how many millions of people have had the virus.
Interestingly, these symptoms often show up when there are no other symptoms present. You might feel fine, but your tongue looks like it’s been through a blender.
We also see these issues in Long Covid. Some people deal with mouth sores or a burning sensation in their mouth for months after the initial infection cleared up. This is likely due to lingering inflammation or a "dysregulated" immune response. Essentially, your body's alarm system is stuck in the "on" position, and your mouth is paying the price.
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Distinguishing It From Other Conditions
Don't panic immediately.
Lots of things cause tongue changes. Stress? Yep. Vitamin B12 deficiency? Definitely. Dehydration or a new toothpaste? Absolutely. If you’ve been slamming acidic coffee and not sleeping, your tongue might look a little ragged regardless of a virus.
The difference with covid tongue is usually the timing. If it appears alongside a headache, fatigue, or a scratchy throat, the connection is much stronger. If you have white patches that you can't scrape off, or if the sores are so painful you can't eat, that's when it's time to talk to a professional.
Real-World Management
What do you actually do if your mouth starts acting up?
First, hydration is non-negotiable. If your mouth is dry, the irritation will get worse. Second, look at your oral hygiene. This isn't the time to skip brushing, but you might want to swap that intense, alcohol-based mouthwash for something gentler. Alcohol dries out the tissue further.
Doctors sometimes prescribe antifungal rinses if they suspect thrush, or topical "magic mouthwash" (a mix of lidocaine and other meds) to numb the pain of ulcers.
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Interestingly, some dentists are the ones spotting this first. Dr. David Strain, a clinical senior lecturer at the University of Exeter, has noted that oral symptoms are a significant marker of how the virus affects the vascular system. If the small blood vessels in your tongue are inflamed, it’s a sign that systemic inflammation is high.
Actionable Steps for Recovery
If you suspect you're dealing with covid tongue or related oral symptoms, here is the roadmap for handling it.
1. Track the Timeline
Document when the changes started. Are they getting better or worse? Take a photo (as awkward as it feels) to show your doctor or dentist. This helps distinguish between an acute infection and a secondary issue like a fungal overgrowth.
2. Optimize Your Oral Environment
Switch to a SLS-free (sodium lauryl sulfate) toothpaste if you have ulcers. SLS is a foaming agent that can irritate open sores. Use a tongue scraper gently to remove that "furry" buildup, but stop if it causes bleeding or pain.
3. Address the Dryness
Use over-the-counter saliva substitutes or lozenges containing xylitol to keep the mouth moist. This protects the enamel of your teeth and helps the soft tissues heal.
4. Nutritional Support
Check your levels of Iron, B12, and Zinc. A viral infection can deplete your body's resources, and deficiencies in these specific nutrients often manifest as tongue inflammation. Adding a high-quality multivitamin can sometimes speed up the repair of the oral mucosa.
5. Professional Consultation
If the patches are persistent, painful, or interfere with swallowing, see a dentist or a primary care physician. They can rule out other causes—like lichen planus or simple bacterial infections—and provide targeted treatments like corticosteroid gels or antifungal medications.
covid tongue is a weird, uncomfortable reminder that viruses don't just stay in the lungs. They move through the whole body. While it's usually not dangerous on its own, it is a clear signal from your immune system that it needs support, rest, and time to recalibrate.