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

Acta Otolaryngol. 2021 Jun;141(6):626-629. doi: 10.1080/00016489.2021.1905178. Epub 2021 Apr 6.

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.

MeSH terms

  • Ageusia / virology
  • COVID-19 / complications*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Olfaction Disorders / virology*
  • Recovery of Function*
  • Sensory Thresholds*