Updated 17th October 2022

What is ‘COVID tongue’ and what does it look like?

Data from millions of users of the ZOE Health Study app contributors has shown that changes to the mouth or tongue can be a symptom of COVID. Here’s how to spot it and what it feels like.

What is COVID tongue?

While less common than other COVID rashes, early in the pandemic some people reported changes to their mouth and tongue. These included mouth ulcers and their tongue appearing coated or patchy (similar to geographical tongue). 

While called COVID tongue, symptoms varied a lot between individuals. Other changes included having a dry mouth and fungal infections (such as oral thrush). Some people also reported pain or muscle aches when chewing. 

An image of suspected 'COVID tongue'

How common is COVID tongue?

During the earlier Alpha wave, ‘COVID tongue’ and mouth ulcers were rare but also acted as a sign of infection.  

Early on in the pandemic, researchers in Spain published a paper reporting that around a quarter of patients hospitalized with COVID had changes to their mouth or tongue. However, we found it to be less common in mild COVID cases. 

Now, COVID tongue remains a very rare symptom with very few people experiencing changes to their mouth or tongue when double or tripled jabbed.   

Mouth ulcers are very common, and many illnesses and infections can cause changes to the surface of the tongue, such as an unexplained condition known as ‘geographic tongue’ that can last for months.

What causes COVID tongue?

It’s not clear what causes COVID tongue or other changes to the mouth such as ulcers or swelling. 

It might be a direct effect of viral infection, or it could be a more general immune related response to being ill. 

Another possibility is that people with COVID may be more susceptible to fungal infections in their mouth (oral thrush), which show up as white blotches, although sufferers often report having been unsuccessfully treated with antifungal drugs

What should I do if I notice changes to my mouth or tongue and think it might be COVID?

It’s vital that people know the current symptoms of COVID now that  restrictions have lifted and access to testing has changed. 

If you’ve noticed strange changes to your tongue, or unusual ulcers, it could be COVID-19, especially if you have any cold-like symptoms.

Download the ZOE Health Study app to log your symptoms, and whether you have COVID or any other bug, please be considerate by staying home when you’re ill and wearing a mask when you go out, to avoid spreading your germs to others who may be more vulnerable.

Help science and keep logging. 

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