Prevalence of Oral Lesions in COVID-19 Patients

Recently, a new coronavirus disease 2019 (COVID-19) has appeared and caused an unprecedented pandemic which is considered as an urgent threat to health authorities worldwide. Several symptoms are observed which are fever, cough, shortness of breath, headache, runny nose, muscle pain, fatigue, arthralgia, sputum production, conjunctivitis, diarrhea. Susceptibility, genetics, systematic diseases, population, gender, and age are crucial considerations for the onset and progression of the viral infection. The patients suffering from asthma or pulmonary deficiency are at high risk of mortality. A metallopeptidase, angiotensin-converting enzyme 2 (ACE2) is considered as the functional receptor for SARS-CoV-2 and it was isolated from a COVID-19 patient. ACE2 was recognized in type I and type II alveolar epithelial cells in both nasal and oral mucosa, in the nasopharynx, in the smooth muscle cells and endothelium of vessels in the stomach and the skin, distinctly in the basal cell layer of the epidermis extending to the basal cell layer of hair follicles, and in the basal layer of the non-keratinizing squamous epithelium. In order to study the possible routes of SARS-CoV-2 infection on the oral mucosa, we investigated whether oral lesions mainly affect the tongue mucosa due to higher ACE2-expressing cell composition and proportion more than that in other oral tissues. Moreover, appearance of oral lesions were as a result of SARS-CoV-2 infection or as a side effect of certain drugs for COVID-19 treatment was evaluated.