Persisting olfactory dysfunction improves in patients 6 months after COVID-19 disease

Abstract

Background: Smell disorders persist in about half of the patients with other symptoms of COVID-19 disease, but the exact duration of the symptoms is yet unknown. Especially, only a few studies used validated olfactory tests for this.

Aims/objectives: The aim of this study was to investigate how many patients with olfactory function impairment, which was detected in a validated olfactory test 3 months after COVID-19 disease, showed improvement in olfactory function after 6 months.

Methods: About 26 patients with a PCR-confirmed, former COVID-19 disease, with an impaired olfactory function after three months, were included in the study. The olfactory function was evaluated with the sniffing sticks test, the taste function with taste sprays.

Results: Smelling function improved in all but one patient (96%). All measured subitems, i.e. olfactory threshold, identification and discrimination of odours significantly improved. In the whole mouth taste test all patients showed normal taste function.

Conclusions and significance: 6 months after COVID-19 disease, olfactory function improves in just about all patients. Long-term measurements must investigate whether complete regeneration of the olfactory function will occur in all patients.

Keywords: Sars-CoV-2; Smell test; Sniffin’ Sticks; long-COVID; smell disorders.