CC BY-NC-ND 4.0 · Int Arch Otorhinolaryngol 2020; 24(03): e391-e392
DOI: 10.1055/s-0040-1713142
Letter to the Editor
Special Article COVID-19
Thieme Revinter Publicações Ltda Rio de Janeiro, Brazil

Olfactory and Taste Disorders in Patients with SARS-CoV-2 Infection

Nazia Begam
1   Department of ENT, ECHS Hospital, Ambala, Haryana, India
2   Department of Community Medicine, MM Institute of Medical Sciences & Research, Mullana, India
› Author Affiliations
Further Information

Publication History

Publication Date:
31 July 2020 (online)

Since December 2019, a pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread globally.[1] [2] A spectrum of disease severity has been reported for the infection, with the main symptoms being fever, fatigue, dry cough, myalgia, and dyspnea.[3]

Previous strains of coronavirus have been demonstrated to invade the central nervous system through the olfactory neuroepithelium and propagate from within the olfactory bulb.[4] Furthermore, nasal epithelial cells display the highest expression of the SARS-CoV-2 receptor, angiotensin-converting enzyme 2, in the respiratory tree.[5]

It has been observed that SARS-CoV-2 does not appear to generate clinically significant nasal congestion or rhinorrhea—that is, a red, runny, stuffy, itchy nose. This observation suggests a neurotropic virus that is site-specific for the olfactory system. Although labeled as a virus that affects the respiratory system, coronaviruses are known to be neurotropic and neuroinvasive.[6] [7] [8] [9]

Olfactory and taste disorders are well known to be related with a wide range of viral infections.[10] [11] In a mice model, SARS-CoV has demonstrated a transneural penetration through the olfactory bulb.[12] Moreover, angiotensin converting enzyme 2 receptor, which is used by SARS-CoV-2 to bind and penetrate into the cell, is widely expressed on the epithelial cells of the mucosa of the oral cavity.[13] These findings could explain the underlying pathogenetic mechanism of taste and olfactory disorders in SARS-CoV-2 infection.

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