study of different local treatments of post covid-19 smell dysfunction

Introduction:this study was designed to differentiate between the impact of the topical nasal spray of corticosteroids, antihistamines, a combination of them, and normal 0.2% saline in treating patients with post-coronavirus disease 2019 (covid-19) smell dysfunction.materials and methods:patients with hyposmia or anosmia (n = 240), who recently recovered from covid-19, were enrolled in this trial and were randomly assigned to four parallel groups. group i (g1) received a combination of topical corticosteroid and antihistamine nasal spray (n = 60). group ii (g2) received topical corticosteroid nasal spray (n = 60). group iii (g3) received antihistamine nasal spray (n = 60). group iv (g4) received 0.2% normal nasal saline nasal spray (n = 60). the treatments were used in all groups for 3 weeks. the sense of smell was assessed using the butanol threshold and discrimination tests. the smell tests were evaluated weekly for 3 weeks.results:the mean age of the patients was 51.9 ± 7.1 years; moreover, 83.8% and 16.3% were male and female, respectively. the results of the smell tests in the first week significantly improved with those in the third week (p< 0.001). the greatest degree of improvement was found in the first group, followed by the second, third, and fourth groups.conclusions:the results suggest the ability of combination therapy of corticosteroid and antihistamine nasal spray to manage post-covid-19 hyposmia or anosmia; however, this combination therapy was not superior to corticosteroid nasal spray. trial registration id: umin000043537