Olfactory Dysfunction and Sinonasal Symptomatology in COVID-19: Prevalence, Severity, Timing, and Associated Characteristics

Abstract

Objective: Olfactory dysfunction (OD)-hyposmia or anosmia-is a symptom of coronavirus disease 2019 (COVID-19), caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We sought to better determine prevalence, severity, and timing of OD in COVID-19 relative to other sinonasal and pulmonary symptoms.

Study design: Prospective, cross-sectional.

Setting: Regional/cantonal hospital.

Subjects: In total, 103 patients diagnosed with COVID-19 with reverse transcription polymerase chain reaction (RT-PCR)-based testing.

Methods: All patients testing positive for COVID-19 at Kantonsspital Aarau over a 6-week period were approached. Timing and severity (at its worst, on scale of 0 [none], 1 [mild], 2 [moderate], and 3 [severe]) of OD, loss of taste, nasal obstruction, rhinorrhea/mucus production, fever, cough and shortness of breath (SOB) were assessed for each patient.

Results: Prevalence of OD was 61.2%, and severity of OD was strongly correlated with severity of loss of taste experienced (ρ = 0.87, P < .001). OD was experienced on the first day of COVID-19 by 8.7% and overall occurred at median infection day 3 (mean, 3.4; range, 0-12). Most experiencing OD reported anosmia, and mean severity of all with OD was moderate to severe (mean [SD], 2.7 [0.6]). Nasal obstruction (49.5%) and rhinorrhea (35.0%) were frequently reported but not correlated with OD. SOB was more severe in patients with OD. OD was associated negatively with older age (OR, 0.96; 95% CI, 0.93-0.99; P = .007) and positively with female sex (OR, 2.46; 95% CI, 0.98-6.19; P = .056).

Conclusions: OD is highly prevalent during COVID-19, occurring early and severely, often in conjunction with loss of taste. OD is associated negatively with older age and positively with female sex. Patients with OD may also experience more severe SOB.

Keywords: COVID-19; SARS-CoV-2; SARS-CoV2; anosmia; coronavirus; gustatory dysfunction; gustatory function; hyposmia; nasal obstruction; olfaction; olfactory dysfunction; olfactory function; rhinorrhea; smell; taste.

Figure 1.

Histogram plots of (A) how long ago participants began experiencing coronavirus disease 2019 (COVID-19) symptoms and (B) how many days into COVID-19 did smell loss begin.

Figure 2.

Bar plots showing the fraction of patients reporting mild, moderate, or severe decrease in sense of (A) smell and (B) taste in patients reporting some decrease in those senses, respectively.

Figure 3.

Bar plots showing fraction of patients reporting mild, moderate, or severe symptoms of decreased sense of smell, decreased sense of taste, nasal obstruction, rhinorrhea, fever, cough, and shortness of breath.

Figure 4.

Correlation plot for severity ratings of symptoms of smell loss, taste loss, nasal obstruction, nasal mucus production, fever, cough, and shortness of breath.