A UK-based epidemiologist has been coming across many COVID patients with oral problems, such as tongue enlargement and discoloration.

Prof. Tim Spector of King’s College London wrote on Twitter, “Seeing increasing numbers of COVID tongues and strange mouth ulcers. If you have a strange symptom or even just headache and fatigue stay at home!”

“My mail is full of tongues each morning from people who had tongue problems that coincided with COVID symptoms like fever and fatigue – but baffled doctors,” he added. “Happy to share so we all become experts …”

About 35% of people have non-characteristic symptoms of COVID in the first 3 days, such as “skin rashes, COVID toes and the 20+ symptoms of COVID that go ignored,” according to Prof. Spector, who is also a science writer.

The U.S. Centers for Disease Control and Prevention (CDC) does not include tongue discoloration or enlargement as symptoms of COVID-19 infection. However, the list of COVID symptoms has grown since the pandemic began.

Infectious disease expert Dr. William Schaffner of Vanderbilt University School of Medicine in Nashville said, “This is kind of in tune with all of the things about COVID. When it burst upon the scene, as I like to say figuratively, we opened up our medical textbooks to COVID, and there were only blank pages,” according to NBC News.

“So since then, we’ve been filling in the blank pages lickety-split, and it may well be that this is part of the clinical syndrome that some patients have,” Dr. Schaffner added.

A Spanish study found that more than 10% of COVID patients had some sort of oral problems, such as mouth ulcers or swollen tongue, according to NBC News. The article was originally published in WebMD.