Coronavirus: are mouth lesions another Covid-19 symptom?

Lesions inside the mouth may be an indicator that a person has contracted the coronavirus, according to a study carried out in Spain.

Six of 21 Covid-19 patients with skin rash also had mouth lesions

Researchers at the Ramón y Cajal University Hospital in Madrid say their findings show that around a third of Covid-19 sufferers found to have a skin rash also turn out to have rash-like oral-cavity lesions, known as enanthems.

"Of 21 patients with Covid-19 and skin rash, 6 patients (29%) had enanthem," researchers said in a paper published in the medical journal JAMA Dermatology last Thursday. “The age range of these patients was between 40 and 69 years, and 4 of the 6 (66%) were women.”

"This work describes preliminary observations and is limited by the small number of cases and the absence of a control group,” they cautioned.

Rash among less common Covid-19 symptoms listed by WHO

According to the World Health Organization (WHO), the most common symptoms of the coronavirus are a fever, a dry cough and tiredness, while the virus’ less common indicators include "a rash on skin, or discolouration of fingers or toes".

Last week, however, a study carried out at King’s College London in the UK called for rashes - known as exanthems when they occur on the outside of the body - to be included as the fourth key symptom of Covid-19.

The research, which is yet to be peer-reviewed, found that 21% of people who had a skin rash and were suffering from Covid-19 reported that this was their only symptom of the disease.

In its findings in JAMA Dermatology, meanwhile, the team at the Ramón y Cajal University Hospital noted that a recent study on patients in Italy had also underlined the apparently regular occurrence of rashes among Covid-19 patients.

Enanthems could help determine if skin rash linked to Covid-19

However, the Madrid study points out that establishing for certain that a skin rash has been brought about by the coronavirus - rather than another cause - is not straightforward. With this in mind, it says, the process of identifying a clear link could be helped by finding out whether or not a patient also has enanthems.

"Whether these manifestations [skin rashes] are directly related to Covid-19 remains unclear, since both viral infections and adverse drug reactions are frequent causes of exanthems," the Spanish researchers explain. "An important clue to distinguish between both entities is the presence of enanthem […]."

Mouths not often checked for safety reasons

They also note, though, that an obstacle towards this is that the insides of mouths are often not checked by medical staff: “Owing to safety concerns, many patients with suspected or confirmed Covid-19 do not have their oral cavity examined.”

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At the time of writing, the coronavirus pandemic had led to 14,974,446 cases and 617,254 deaths worldwide. You can stay up-to-date with the latest developments in the Covid-19 crisis by following our dedicated daily blogs for the United States, Africa and India.