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Post-viral olfactory loss and parosmia

The emergence of SARS-CoV-2 has brought olfactory dysfunction to the forefront of public awareness, because up to half of infected individuals could develop olfactory dysfunction. Loss of smell—which can be partial or total—in itself is debilitating, but the distortion of sense of smell (parosmia) t...

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Autores principales: Liu, Zhen Yu, Vaira, Luigi Angelo, Boscolo-Rizzo, Paolo, Walker, Abigail, Hopkins, Claire
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BMJ Publishing Group 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10568123/
https://www.ncbi.nlm.nih.gov/pubmed/37841969
http://dx.doi.org/10.1136/bmjmed-2022-000382
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author Liu, Zhen Yu
Vaira, Luigi Angelo
Boscolo-Rizzo, Paolo
Walker, Abigail
Hopkins, Claire
author_facet Liu, Zhen Yu
Vaira, Luigi Angelo
Boscolo-Rizzo, Paolo
Walker, Abigail
Hopkins, Claire
author_sort Liu, Zhen Yu
collection PubMed
description The emergence of SARS-CoV-2 has brought olfactory dysfunction to the forefront of public awareness, because up to half of infected individuals could develop olfactory dysfunction. Loss of smell—which can be partial or total—in itself is debilitating, but the distortion of sense of smell (parosmia) that can occur as a consequence of a viral upper respiratory tract infection (either alongside a reduction in sense of smell or as a solo symptom) can be very distressing for patients. Incidence of olfactory loss after SARS-CoV-2 infection has been estimated by meta-analysis to be around 50%, with more than one in three who will subsequently report parosmia. While early loss of sense of smell is thought to be due to infection of the supporting cells of the olfactory epithelium, the underlying mechanisms of persistant loss and parosmia remain less clear. Depletion of olfactory sensory neurones, chronic inflammatory infiltrates, and downregulation of receptor expression are thought to contribute. There are few effective therapeutic options, so support and olfactory training are essential. Further research is required before strong recommendations can be made to support treatment with steroids, supplements, or interventions applied topically or injected into the olfactory epithelium in terms of improving recovery of quantitative olfactory function. It is not yet known whether these treatments will also achieve comparable improvements in parosmia. This article aims to contextualise parosmia in the setting of post-viral olfactory dysfunction, explore some of the putative molecular mechanisms, and review some of the treatment options available.
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spelling pubmed-105681232023-10-13 Post-viral olfactory loss and parosmia Liu, Zhen Yu Vaira, Luigi Angelo Boscolo-Rizzo, Paolo Walker, Abigail Hopkins, Claire BMJ Med Specialist Review The emergence of SARS-CoV-2 has brought olfactory dysfunction to the forefront of public awareness, because up to half of infected individuals could develop olfactory dysfunction. Loss of smell—which can be partial or total—in itself is debilitating, but the distortion of sense of smell (parosmia) that can occur as a consequence of a viral upper respiratory tract infection (either alongside a reduction in sense of smell or as a solo symptom) can be very distressing for patients. Incidence of olfactory loss after SARS-CoV-2 infection has been estimated by meta-analysis to be around 50%, with more than one in three who will subsequently report parosmia. While early loss of sense of smell is thought to be due to infection of the supporting cells of the olfactory epithelium, the underlying mechanisms of persistant loss and parosmia remain less clear. Depletion of olfactory sensory neurones, chronic inflammatory infiltrates, and downregulation of receptor expression are thought to contribute. There are few effective therapeutic options, so support and olfactory training are essential. Further research is required before strong recommendations can be made to support treatment with steroids, supplements, or interventions applied topically or injected into the olfactory epithelium in terms of improving recovery of quantitative olfactory function. It is not yet known whether these treatments will also achieve comparable improvements in parosmia. This article aims to contextualise parosmia in the setting of post-viral olfactory dysfunction, explore some of the putative molecular mechanisms, and review some of the treatment options available. BMJ Publishing Group 2023-07-20 /pmc/articles/PMC10568123/ /pubmed/37841969 http://dx.doi.org/10.1136/bmjmed-2022-000382 Text en © Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. https://creativecommons.org/licenses/by-nc/4.0/This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (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, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/ (https://creativecommons.org/licenses/by-nc/4.0/) .
spellingShingle Specialist Review
Liu, Zhen Yu
Vaira, Luigi Angelo
Boscolo-Rizzo, Paolo
Walker, Abigail
Hopkins, Claire
Post-viral olfactory loss and parosmia
title Post-viral olfactory loss and parosmia
title_full Post-viral olfactory loss and parosmia
title_fullStr Post-viral olfactory loss and parosmia
title_full_unstemmed Post-viral olfactory loss and parosmia
title_short Post-viral olfactory loss and parosmia
title_sort post-viral olfactory loss and parosmia
topic Specialist Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10568123/
https://www.ncbi.nlm.nih.gov/pubmed/37841969
http://dx.doi.org/10.1136/bmjmed-2022-000382
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