Systematic Reviews
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World J Virol. Sep 25, 2022; 11(5): 362-374
Published online Sep 25, 2022. doi: 10.5501/wjv.v11.i5.362
Anatomophysiological relationships and clinical considerations of taste and smell loss in patients with COVID-19
Maria Fernanda Rossi Vigliar, Karina Torres Pomini, Daniela Vieira Buchaim, Rogerio Leone Buchaim
Maria Fernanda Rossi Vigliar, Karina Torres Pomini, Rogerio Leone Buchaim, Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru 17012901, São Paulo, Brazil
Karina Torres Pomini, Daniela Vieira Buchaim, University of Marilia, Marilia 17525902, São Paulo, Brazil
Daniela Vieira Buchaim, University Center of Adamantina, Adamantina 17800000, São Paulo, Brazil
Rogerio Leone Buchaim, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508270, São Paulo, Brazil
Author contributions: Vigliar MFR and Buchaim RL conceptualized, designed, and contributed to the outline of the review article; Pomini KT and Buchaim DV contributed to drafting, editing, and formatting of the manuscript; all authors wrote, read, and approved the final manuscript.
Conflict-of-interest statement: All authors declare no conflicts of interest for this article.
PRISMA 2009 Checklist statement: All authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Rogerio Leone Buchaim, PhD, Associate Professor, Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Alameda Dr. Octávio Pinheiro Brisolla 9-75, Bauru 17012901, São Paulo, Brazil. rogerio@fob.usp.br
Received: April 13, 2022
Peer-review started: April 13, 2022
First decision: June 16, 2022
Revised: June 24, 2022
Accepted: August 12, 2022
Article in press: August 12, 2022
Published online: September 25, 2022
Processing time: 163 Days and 17.2 Hours
Abstract
BACKGROUND

There are numerous conflicting discussions about the outbreak of the new coronavirus 2019 (COVID-19).

AIM

To present some anatomical and physiological considerations about two of the symptoms reported by patients: The loss or reduction of smell and taste.

METHODS

The loss or reduction of smell and taste is presented in a peculiar way, with some cases of persistence even after COVID-19. For this, it was searched in three databases, PubMed/MEDLINE, Web of Science, and Scopus, using the following keywords: "Smell", "Taste", "Smell AND COVID-19", "Taste AND COVID-19", with no publication time restriction, only in English with full text available, excluding also brief communications, letters to the editor, editorials, reviews, comments, and conference abstracts.

RESULTS

The search found 776 articles in the PubMed/MEDLINE database, 1018 in the Web of Science database, and 552 in the Scopus database, from which duplicates were removed (104 articles). Finally, 17 studies were selected for detailed analysis within the eligibility criteria, with titles and abstracts related to central nervous system lesions responsible for smell and taste. This review suggests that viral mechanisms of action may be related to lesions both at the local level and at the level of the central nervous system, lasting up to 3 to 4 wk. It is considered persistent if it exceeds this period, as reported in one case in this review. There are still few studies about the treatment, and among those addressed in this review, only two studies reported possible treatments and emphasized the scarcity of data, with the best option being treatments that do not cause harm, such as gustatory and olfactory physiotherapy

CONCLUSION

Given the scarcity of data, this review emphasizes the importance of prevention, through the correct use of personal protective equipment by health professionals and respect for local behavioral indications. It is also emphasized, through five studies, that there is a predominance of such symptoms in patients with COVID-19, which can be a tool to control dissemination, through the early isolation of patients until the results are ready.

Keywords: SARS-CoV-2; COVID-19; Coronavirus; Olfactory nerve; Smell; Taste

Core Tip: We discuss the anatomical and physiological considerations about two of the symptoms reported by patients: The loss or reduction of smell and taste. There are still few studies about the treatment, and among those addressed in this review, only two studies reported possible treatments and emphasized the scarcity of data, with the best option being treatments that do not cause harm, such as gustatory and olfactory physiotherapy. Given the scarcity of data, this review emphasizes the importance of prevention, through the correct use of personal protective equipment by health professionals and respect for local behavioral indications. It is also emphasized, through five studies, that there is a predominance of such symptoms in patients with coronavirus disease 2019, which can be a tool to control dissemination, through the early isolation of patients until the results are ready.