The coronavirus disease 2019: the prevalence, prognosis, and recovery from olfactory dysfunction (OD).

Background: Many patients with coronavirus disease 2019 (COVID-19) complain from olfactory dysfunction (OD). Aims/objectives: To evaluate the prevalence, prognosis, and recovery from OD in COVID-19 patients.
Material and Methods: In this study, patients with COVID-19 symptoms who were referred to six different tertiary referral centres were recruited after positive results for COVID-19. All patients were assessed for a one-month follow-up after the initial diagnosis of COVID-19.
Results: Three hundred and eleven patients with COVID-19 were recruited in the present study. Two hundred and seven patients (66.6%) had a recent history of OD. One hundred and seventy-eight patients had experienced OD as a primary symptom intercurrent to other COVID-19 symptoms or solely. Sixty-nine patients had OD at the time of presentation to referral centres. Headache and nasal obstruction had significant relationships with recovery from OD in this subgroup, and the platelet count was the most important predictor for the recovery from OD. One hundred seventy-nine (86.4%) patients were nearly or fully recovered from OD approximately a month after the onset of OD.
Conclusion: Headache, nasal obstruction, and platelet count may have specific roles as prognostic factors in the recovery from OD.