The temporal course of COVID-19 anosmia and relation to other clinical symptoms

Abstract

Objective This study aimed to define the clinical course of anosmia in relation to other clinical symptoms. Methods 135 patients with COVID-19 were reached by phone and subsequently included in the study. Olfactory functions were evaluated using a questionnaire for assessment of self-reported olfactory function. Patients were divided into four subgroups according to the presence of olfactory symptoms and temporal relationship with the other symptoms: group1 had only olfactory complaints (isolated, sudden-onset loss of smell); group2 had sudden-onset loss of smell, followed by COVID-19 related complaints; group3 initially had COVID-19 related complaints, then gradually developed olfactory complaints; and group4 had no olfactory complaints. Results In total, 59.3% of the patients interviewed had olfactory complaints during the disease course. The olfactory dysfunction severity during COVID-19 infection was significantly higher in group1 compared to groups 2 and 3. In groups1-3, the odor scores after recovery from COVID-19 disease were significantly lower compared to the status prior to disease onset. The residual olfactory dysfunction was similar between groups1 and 2, but was more evident than group3. Mean duration for loss of smell was 7.8 ± 3.1 (2-15) days. Duration of loss of smell was longer in groups1 and 2 than in group3. Odor scores completely returned back to the pre-disease values in 41 (51.2%) patients with olfactory dysfunction. Rate of complete olfactory dysfunction recovery was higher in group3 compared to groups1 and 2. Conclusion In isolated anosmia cases, anosmia is more severe, and complete recovery rates are lower compared to the patients who have other clinical symptoms. Level of evidence Level 4.

Effect of nasal corticosteroid in the treatment of anosmia due to COVID-19: A randomised double-blind placebo-controlled study

“…Our data broadly support the hypothesis that younger patients have better local immunological response, which produces a stronger local inflammatory reaction and thereby manifested as olfactory dysfunction [ 25 , 28 ]. The higher presentation of anosmia in females could be attributed to the fact that women are more sensitive to changes in the sense of smell than men [ 29 ]. Another important characteristic of our study population is the high association of anosmia with gustatory dysfunction, ageusia, which presented in 84.8% of the patients ( Table 1 ).…”

Smell and Taste Loss Recovery Time in COVID-19 Patients and Disease Severity

“…We found no significant association between olfactory dysfunction and the presence of nasal blockage. Altundag et al, though, reported that nasal congestion was found to be more prevalent in cases with olfactory dysfunction compared to patients without olfactory dysfunction [ 19 ]. We found that smell loss significantly correlated with taste loss and rhinorrhea.…”

Anosmia as a predictor for post-COVID-19 fatigue syndrome

“…Anosmia usually shows spontaneous improvement over a 2–3 week period [2] . However, some COVID-19 patients remain anosmic for longer time periods [2] .…”

“…Anosmia usually shows spontaneous improvement over a 2–3 week period [2] . However, some COVID-19 patients remain anosmic for longer time periods [2] . The most likely explanation is that in those cases, a larger area of the olfactory epithelium is affected, possibly with a more profound destruction of the epithelium that included death of a larger number of olfactory receptor neurons [3] .…”