Assessment of olfactory and gustatory functions in COVID-19 patients

Background Olfactory and gustatory disorders are common problems encountered during the COVID-19 pandemic with a significant impact on the patient's quality of life: The aim of this study was to assess the olfactory and gustatory functions in COVID-19 patients with correlation between them and clinical and laboratory markers. This was a cross-sectional study conducted on 63 subjects recruited from the COVID-19 clinics at Police Authority and Menoufia University hospitals. The patients were assessed using history taking, anterior rhinoscopy, endoscopic examination, computed tomography, and polymerase chain reaction (PCR) test. Olfactory functions were assessed using the alcohol threshold test. Gustatory functions were assessed using the three-drop method. The olfactory and gustatory functions were correlated with age, gender, and laboratory parameters. Also, the recovery of smell and taste disorders was correlated with our assessed laboratory markers.Results The prevalence of olfactory dysfunction among study participants was 41 patients (65%) of the participants including 12 patients (19.1%) having mild hyposmia, 10 patients (15.8%) having moderate hyposmia, 9 patients (14.3%) having severe hyposmia, and 10 patients (15.8%) having complete anosmia. The prevalence of gustatory dysfunction among study participants was 24 patients (38.1%). Age, gender, and laboratory parameters did not show any statistically significant difference between those who experienced olfactory dysfunction or gustatory dysfunction and those who did not. However, there was a significant positive correlation between the total leucocytic count, serum level of CRP, and serum level of D-dimer and the degree of olfactory dysfunction (0.049, 0.03, and 0.02, respectively). There was a nonsignificant correlation between recovery of olfactory and gustatory dysfunction and laboratory markers.Conclusion Olfactory and gustatory dysfunction are established clinical presentations among COVID-19-positive patients. The laboratory markers had no correlation with the incidence of these dysfunctions or their recovery. However, TLC, serum CRP, and serum D-dimer had a significant positive correlation with the severity of olfactory dysfunction.