Olfactory dysfunction (OD) – the reduced ability to smell – has been reported in patients with COVID-19. However, our understanding of its severity, cause and duration remains poor. A team of experts from HKUMed studied the ability to smell in 18 patients with COVID-19 and reviewed the findings of OD from published peer-reviewed articles.
Key takeaways from the study:
- The median time from common symptoms of COVID-19 first appearing to olfactory symptoms was 0.5 days
- 67% (12/18) of patients experienced olfactory symptoms
- 17% (2/12) of patients with olfactory symptoms were reported to have runny or stuffy nose
- 75% (9/12) of patients were reported to have lost their sense of taste
- The average Butanol Threshold Test (BTT) score– a test to assess the sense of smell – was higher in healthy people (meaning they had a better sense of smell) than in patients with COVID-19 (5.9 vs 4.1)
- Younger patients with COVID-19 (<22 years) appeared to have lower BTT scores than older patients, meaning younger patients had a worse sense of smell than older patients
In a comprehensive review of published articles on peer-reviewed journals, approximately 5–98% of patients with COVID-19 were reported to experience some form of reduced sense of smell.
Overall, this study showed that OD is a common symptom in patients with COVID-19, but stuffy or runny nose was less common in most patients. Studies have linked OD to depression or lower quality of life; therefore, it is important that OD is treated in patients with COVID-19.
To read the original article published in Open Forum Infectious Diseases, click here.
