As the Covid-19 pandemic continues to cause unprecedented damage to lives across the world, scientists are still learning about the various symptoms of the viral infection. Of late, there have been cases where patients have experienced newer symptoms after being infected with the coronavirus. The latest report by the National Institute of Health mentions that about half of the patients have these symptoms.
One of them is dry mouth, also known as Xerostomia, which could be the initial presentation of COVID 19. Patients may develop this condition even a few days ahead of fever, sore throat, or other known or associated symptoms.
“In a dry mouth, the body is unable to produce saliva which protects the mouth from bad bacteria, other pathogens and aids the process of digestion. The patient may feel dryness or stickiness in the mouth and the saliva may become thicker. As per studies, Xerostomia happens when the virus attacks the oral linings and muscle fibres,” said Dr Samrat Shah, consultant internist at Bhatia Hospital, Mumbai.
The other most common causes of dry mouth include drugs, type 1 diabetes, hyperthyroidism, autoimmune diseases, renal failure, vitamin deficiencies, and other viral infections. However, in recent times, there have been a number of cases of dry mouth related to COVID-19, which has caught the attention of researchers.
“Research has shown that other than the common organs, ACE2 or angiotensin-converting enzyme 2 exists in various oral mucosal tissues, so, the oral cavity is considered a potential route for the entry of the COVID-19 virus. ACE2 is a protein that provides the entry point for the coronavirus to hook into and infect a wide range of human cells,” mentioned Dr Shah.
Like dry mouth, another symptom of dry tongue — now also known as COVID tongue — is a manifestation when the body fails to produce saliva that protects your mouth from bad bacteria. COVID tongue is often accompanied by a change to the tongue’s sensation, as well as muscle pain while chewing due to persistent ulcers. In this condition, the tongue may start to appear white and patchy. However, in many cases, this disorder is due to alterations in the quality of saliva, while the quantity of saliva does not vary much.
People who have developed dry mouth or dry tongue may also find it difficult to chew food and speak. The ACE2 receptors are mostly observed in the tongue and floor of the mouth, among other areas.
Studies have shown that these receptors are also present in salivary gland cells which are believed as one of the first SARS-CoV-2 target cells. Since xerostomia could occur before the common symptoms are noticed, it is possible to use this condition for early diagnosis, treatment, and isolation of the individual thereby preventing further transmission.
Some of the other reasons that researchers have suggested for the occurrence of xerostomia in COVID-19 is the consumption of numerous medicines and diverse pharmacological groups. “The most common medications in patients with COVID-19 include antiviral agents (remdesivir), hydroxychloroquine, anti-HIV medications (ritonavir, lopinavir) and interferons. Overall, these medications are the most frequent reasons for xerostomia,” said Dr Shah.
However, as mentioned earlier, the signs of xerostomia in COVID-19 patients usually occur before other symptoms. This means it is possible to initiate treatment faster. This could reduce the possibility of the need for medicines that could generate xerostomia. However, in some cases, studies have also shown that the signs of xerostomia began simultaneously or a little after the incidence of COVID-19 symptoms.
For now, it’s important to know that COVID is not merely a respiratory infection. Besides lungs, it also affects blood vessels and other body organs, hence it can manifest in symptoms which even experts had no idea about.