Olfactory and Gustatory Dysfunction in COVID-19 Patients – A Current Review

Author(s): Tay Yong Boon Ernest, Ho Ching Wen Dawn, Rebecca Low Pei Kee, Bharath Raj Varatharaj Palraj, Ramkumar Sekar, Muhammad Bilal Abid, Veeraraghavan Meyyur Aravamudan, Charn Tze Choong

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a novel coronavirus that has caused a global pandemic. Initial reported symptoms include fever, cough, dyspnoea, fatigue, and myalgia. There has been increasing evidence that sudden olfactory and gustatory dysfunction may be another common symptom. This review will look at the prevalence of olfactory and gustatory dysfunction in COVID-19, the utility of this symptom as a screening tool for the disease, postulated disease mechanisms resulting in olfactory and gustatory dysfunction, and the recovery rate of smell or taste dysfunction in these patients.

Methods A review of relevant articles was conducted via a search through MEDLINE, EMBASE, CENTRAL, and Web of Science. References of articles were also examined to identify other relevant publications.

Results There is a high prevalence for olfactory or gustatory dysfunction among COVID-19 patients, although clinical data may represent indigenous variability in geographical regions, demographic features, and clinical severity. And patients exhibiting these disturbances as the first or only symptom may have a milder disease course. SARS-CoV-2 is postulated to be a neurotropic virus with a specific tropism for the olfactory system.

Conclusion Current literature suggests olfactory and gustatory dysfunction is prevalent in COVID-19. Longer term data is required to draw definitive conclusions about this association.