Evolution of Olfactory Disorders in COVID-19 Patients

Abstract

Objectives: A high frequency and a strong association of olfactory/gustatory impairment with COVID-19 were reported. Its spontaneous evolution remains unknown. The aim of this study was to investigate the spontaneous evolution of olfactory disorders in COVID-19 patients.

Study design: Cross-sectional study.

Methods: A total of 229 patients with laboratory-confirmed COVID-19 from March 1 through 31, 2020 in our institution were included. Among them, 140 patients (mean age, 38.5 years, 89 women) reported sudden olfactory/gustatory disorders during COVID-19. All patients were interviewed by phone based on a questionnaire with 16 questions at time of survey. The primary end point was olfactory recovery rate at time of survey.

Results: The frequency of patients with olfactory disorders was higher before March 20, 2020 than since (70.3% vs. 53.9%, respectively) (P = .016). At time of survey (26 days of the mean time from anosmia onset), 95.71% reported to start an olfactory recovery. The mean time from olfactory loss onset to recovery onset was 11.6 days. Recovery started between the fourth and the fifteenth day after olfactory loss onset in 78.4% of patients. Complete olfactory recovery happened for 51.43% of patients. There was a significant relationship between the complete olfactory recovery and a short time from olfactory loss onset to recovery onset (P = .0004), absence of nasal obstruction (P = .023) and absence of sore/dry/tingling feeling in the nose (P = .007) in COVID-19 patients.

Conclusion: Knowledge of spontaneous evolution of olfactory disorders allows reassuring patients and planning therapeutic strategies for persistent olfactory dysfunction after having definitely recovered from COVID-19.

Level of evidence: 4 Laryngoscope, 130:2667-2673, 2020.

Keywords: Olfactory disorders, olfactory dysfunction, COVID-19, olfactory recovery, anosmia.