This systematic review purposed to investigate reports of oral lesions in confirmed COVID-19 patients summarizing clinical characteristics, histological findings, treatment and correlation of oral lesions and COVID-19 severity. Electronic search was conducted on November 2021 using seven databases to identify case reports/series describing lesions in oral mucosa in COVID-19 confirmed cases. A total of 5,179 studies were found, being 39 eligible from 19 countries, totalling 116 cases. It was observed only COVID-19 non-vaccinated cases and no sex or age predilection. The oral lesions presentation was mostly single location (69.8%), commonly in the tongue, lips, and palate, being ulcer the main clinical presentation. According to severity index for COVID-19, the reports were more frequent in patients with mild and moderate symptoms, being 75.8% in acute phase. The oral lesion appearance in post-acute COVID-19 were described after 14 to two months after patient recovery. Histologically, keratinocytes with perinuclear vacuolization, thrombosis and mononuclear inflammatory infiltrate were also described with the presence of the virus in keratinocytes, endothelial cells, and minor salivary glands. In conclusion, health care professionals should consider COVID-19 association when patient present ulcerated oral lesions and mild to moderate symptoms for COVID-19 or had acute-COVID-19.
