Evidence builds for anosmia as a clue to mild-moderate COVID-19

  • Lechien JR & al.
  • Ann Intern Med
  • 26 May 2020

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • Olfactory dysfunction in patients with mild-to-moderate COVID-19 might be more widespread than previously believed and occurring in multiple clinical forms.
  • Studies are needed to assess pathological mechanisms, viral spread through olfactory neuroepithelium, invasion of olfactory bulb, and central nervous system.

Why this matters

  • Clinicians should be alert to loss of smell and taste as symptoms of mild-to-moderate COVID-19.

Key results

  • 2013 participants; 8% (161) were hospitalized for COVID-19.
    • 87.2% reported loss of smell.
    • 56.4% reported taste dysfunction. 
  • Mean time from end of disease to evaluation: 7.8 (standard deviation [SD], 6.8) days.
  • Mean duration of nonolfactory symptoms: 11.5 (SD, 6.0) days.
  • 65.4% who had olfactory dysfunction did so after other general or otolaryngologic symptoms
  • 573 patients regained sense of smell:
    • 60.9% of this group regained sense of smell at 5-14 days after loss (mean duration, 8.4 [SD, 5.1] days).
  • Of 86 patients completing an objective olfactory evaluation:
    • 47.7% had confirmed anosmia. 
    • 14.0% had confirmed hyposmia. 
    • 38.3% had no signs of dysfunction.
  • No significant association was identified between loss of smell and nasal obstruction, rhinorrhea, or postnasal drip. 

Study design

  • Cross-sectional evaluation of prevalence, features, recovery from smell dysfunction in hospitalized and ambulatory patients recovering from mild-to-moderate COVID-19 in Europe, March 22, 2020 to April 23, 2020.
  • Funding: None disclosed.

Limitations

  • Self-report bias.
  • Generalizability unknown.