Olfactory Dysfunction: A Highly Prevalent Symptom of COVID‐19 With Public Health Significance

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p> Coronavirus disease 2019 (COVID-19) is a global pandemic affecting millions of individuals, killing hundreds of thousands. Although typically described with characteristic symptoms of fever, cough, and shortness of breath, greater understanding of COVID-19 has revealed myriad clinical manifestations. Olfactory dysfunction (OD)—hyposmia and anosmia—has recently been recognized as an important symptom of COVID-19 and increasingly gained traction as a public health tool for identifying COVID-19 patients, in particular otherwise asymptomatic carriers who, unawares, may be major drivers of disease spread. The objective of this study is to review the scientific evidence about anosmia in COVID-19. </jats:p></jats:sec><jats:sec><jats:title>Data Sources</jats:title><jats:p> PubMed, Google Scholar, and Web of Science. </jats:p></jats:sec><jats:sec><jats:title>Review Methods</jats:title><jats:p> Comprehensive literature search of primary studies pertinent to the objectives of this review using the chosen data sources. </jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p> Current evidence shows that OD is highly prevalent in COVID-19, with up to 80% of patients reporting subjective OD and objective olfactory testing potentially showing even higher prevalence. OD is frequently accompanied by taste dysfunction. Up to 25% of COVID-19 patients may experience sudden-onset OD as the first symptom. A large proportion of COVID-19 OD cases may resolve over the period of a few weeks. </jats:p></jats:sec><jats:sec><jats:title>Implications for Practice</jats:title><jats:p> Sudden anosmia should be considered a symptom of COVID-19. Assessing for sudden-onset anosmia may increase sensitivity of COVID-19 screening strategies, in particular for identifying patients at the earliest stages of disease. Since many cases of OD due to COVID-19 may resolve in the short term, conservative management, including observation, is reasonable, while advanced imaging is unnecessary. </jats:p></jats:sec>

Mood, Anxiety and Olfactory Dysfunction in COVID‐19: Evidence of Central Nervous System Involvement?

“…6,28,29 OD in the setting of COVID-19 is also highly correlated with decreased sense of taste. 6,28,29 Participants from this cohort have been previously studied with respect to the prevalence, timing, and severity of sinonasal symptoms as well as classic COVID-19 symptoms of fever, cough, and shortness of breath. 19 The prevalence of OD was comparable to past studies, and we also found that OD was quite severe when it occurred.…”

“…[1][2][3] COVID-19 has classically been described by symptoms of fever, cough, and shortness of breath as well as constitutional symptoms such as fatigue and myalgias, 2,4,5 although more recent studies have described a myriad of other COVID-19 clinical manifestations including chemosensory dysfunction, ie, decreased sense of smell and taste. 6 With a mortality rate that is widely publicized and understood in the lay public to be an order of magnitude greater than influenza, COVID-19 may be a significant source of emotional strain on the affected individual. Previous studies of endangering diseases, such as cancer, diabetes, or heart disease, have found that affected patients experience much higher rates of depression and anxiety.…”

Olfactory disorders in coronavirus disease 2019 patients: a systematic literature review

“…A small number of systematic reviews [6][7][8][9][10][11][12] have been published already, during the early stages of the pandemic in Europe and USA. However, in light of continuous scientific updating, we believe that our study can provide a more holistic approach to current knowledge of the disease.…”

Olfactory Bulb Signal Abnormality in Patients with COVID-19 Who Present with Neurologic Symptoms

“…[4][5][6][7][8][9][10][11] Chemosensory symptoms may present as viral prodromes or be concomitant with the development of other disease symptoms. 12 Although olfactory dysfunction can be seen with rhinoviruses, parainfluenza, Epstein-Barr virus, and other coronaviruses, this symptom is typically linked with rhinorrhea and nasal obstruction, whereas there is accumulating evidence that SARS-CoV-2 associated olfactory dysfunction is seen independent of nasal congestion. 2,6 Anosmia in the absence of other symptoms is reported in as many as 1 of 6 individuals with SARS-CoV-2 infection.…”