Smell and taste disorders in COVID-19: From pathogenesis to clinical features and outcomes

Neurosci Lett. 2021 Mar 23:748:135694. doi: 10.1016/j.neulet.2021.135694. Epub 2021 Feb 15.

Abstract

Patients with COVID-19 often complain of smell and taste disorders (STD). STD emerge early in the course of the disease, seem to be more common in SARS-CoV-2 infection than in other upper respiratory tract infections, and could in some cases persist for long after resolution of respiratory symptoms. Current evidence suggests that STD probably result from a loss of function of olfactory sensory neurons and taste buds, mainly caused by infection, inflammation, and subsequent dysfunction of supporting non-neuronal cells in the mucosa. However, the possible occurrence of other mechanisms leading to chemosensory dysfunction has also been hypothesized, and contrasting data have been reported regarding the direct infection of sensory neurons by SARS-CoV-2. In this mini-review, we summarize the currently available literature on pathogenesis, clinical manifestations, diagnosis, and outcomes of STD in COVID-19 and discuss possible future directions of research on this topic.

Keywords: Ageusia; Anosmia; COVID-19.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • COVID-19 / complications*
  • COVID-19 / immunology
  • COVID-19 / virology
  • Humans
  • Mouth Mucosa / immunology
  • Mouth Mucosa / pathology
  • Olfaction Disorders / diagnosis
  • Olfaction Disorders / epidemiology
  • Olfaction Disorders / etiology*
  • Olfaction Disorders / physiopathology
  • Olfactory Mucosa / immunology
  • Olfactory Mucosa / pathology
  • Olfactory Receptor Neurons / immunology
  • Olfactory Receptor Neurons / pathology
  • SARS-CoV-2 / immunology
  • SARS-CoV-2 / pathogenicity*
  • Smell / physiology
  • Taste / physiology
  • Taste Buds / immunology
  • Taste Buds / pathology
  • Taste Disorders / diagnosis
  • Taste Disorders / epidemiology
  • Taste Disorders / etiology*
  • Taste Disorders / physiopathology