Corticosteroid nasal irrigation as early treatment of olfactory dysfunction in COVID-19: A prospective randomised controlled trial

Objective: This study aimed to evaluate the efficacy of corticosteroid irrigation compared to saline to no nasal irrigation in COVID-19 patients with olfactory loss. Design and Setting: A randomised controlled study was conducted at the Otolaryngology-Head & Neck Surgery Department, Ramathibodi Hospital, Faculty of Medicine, Mahidol University. Participants: Two hundred thirty-seven COVID-19 participants with a new-onset smell loss were recruited into the study. Two hundred twenty-two participants met the inclusion criteria and were randomised into three groups: corticosteroid irrigation, saline irrigation and no treatment. Main Outcome Measures: The primary outcome was the mean difference in the smell sensation score among the groups after treatment at 1, 2 and 6 weeks. The secondary outcomes measurements included (1) a self-rating quality of life (QOL)-related smell dysfunction score, (2) the change over time in smell sensation score and self-rating QOL-related smell dysfunction score and (3) the median time to complete recovery of smell loss. Results: The mean differences in smell sensation scores among the three groups were not statistically significant at any follow-up period. The mean score of self-rating QOL-related smell dysfunction in the corticosteroid group was significantly better than the other groups at 1 week. The change of outcome scores showed significant improvement over time, regardless of the treatments. The median time to complete smell recovery was similar: 3 weeks. Conclusion: This study emphasised that corticosteroid nasal irrigation is not superior to saline or no nasal irrigation in restoring the sense of smell in COVID-19-associated olfactory loss.