Introduction:
Among other etiologies, such as the airway obstruction and neural disorders, viral illnesses have always been the most common cause of prolonged olfactory dysfunction (POD). The emerging coronavirus disease 2019 (COVID-19), which is now increasingly recognized to be accompanied by an impairment in odor sensation, may have contributed to an increase in the overall prevalence of POD, but to what extent is unknown. While once thought to have a good prognosis, recent reports on long-term follow-up data estimate that a significant proportion of patients with the COVID-19-related odor sensation impairment, ranging from 1% to 48%1,2, develop POD. In this study, we evaluated the relative burden of the COVID-19-related disease in a single-centered cohort consisting of patients with POD of previously undetermined etiology. The clinical characteristics of COVID-19-related POD were compared with those of POD from other etiologies.