Background: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a viral infection involving multi-organ manifestations. The main oral symptoms of COVID-19 associated are taste loss and xerostomia, but literature has reported other oral manifestation, such as oral blisters, ulcers, vesicles and other immunological lesions. This case report showed an Erythema Multiforme (EM) manifesting as oral mucosa lesions in a patient with a late diagnosis of COVID-19 infection. Case Presentation: A 30 years-old Caucasian woman was sent to an oral medicine office, in order to manage painful and oral mucosa lesions associated with target symmetrical skin lesions. Oral examination revealed extensive ulcers in the mouth and crusts on the lips. Based on clinical examinations, a diagnosis of Erythema Multiforme major was made and a drug therapy with steroids was administered. Five days after the specialist visit, the patient discovered that she was positive for COVID-19. The complete recovery occurred in 3 weeks. Conclusion: Confirming the literature studies, EM is an early disease associated with COVID-19 infection.
