Mechanisms of COVID-19-associated olfactory dysfunction.

Area of Science:

• Neurology
• Infectious Diseases
• Otorhinolaryngology

Background:

• Olfactory dysfunction is a hallmark symptom of COVID-19, significantly impacting patients' quality of life.
• While less common with Omicron variants, persistent smell and taste disorders remain a significant health issue.
• Understanding the underlying causes is crucial for developing effective treatments.

Purpose of the Study:

• To comprehensively review the epidemiology of COVID-19-associated olfactory dysfunction.
• To describe the clinical manifestations of smell and taste disorders post-COVID-19.
• To summarize current knowledge on the pathogenic mechanisms of olfactory dysfunction.

Main Methods:

• Literature review of studies on COVID-19 and olfactory dysfunction.
• Analysis of epidemiological data and clinical case reports.
• Synthesis of research on viral impact on the olfactory system.

Main Results:

• Olfactory dysfunction was highly prevalent early in the pandemic but decreased with Omicron variants.
• Mechanisms include sustentacular cell infection, inflammation, and potential long-term effects on olfactory neurons and brain regions.
• Persistent dysosmia and dysgeusia highlight the need for continued research.

Conclusions:

• COVID-19-associated olfactory dysfunction, though less frequent now, presents complex and multifactorial pathogenic mechanisms.
• Both acute and persistent forms require further investigation to address ongoing patient concerns.
• This review provides a foundation for understanding and managing long-term olfactory deficits.