Olfactory disorders in COVID-19
Reviewed by Sunil Sharma

This Turkish prospective longitudinal observational study evaluated olfactory disorders (OD) and recovery processes in patients with COVID-19 infection at three time points within the first month of diagnosis: time of diagnosis with positive PCR test; time of first negative PCR test; and one month after initial diagnosis. Patients who required ICU admission were excluded from the study. There were 96 patients followed in the study, and olfactory function and quality of life (QoL) was measured using the National Health and Nutrition Examination Survey, Questionnaire of Olfactory Disorders – Negative Statements (QOD-NS), and the Sino-Nasal Outcome Test (SNOT)-22. At the point of diagnosis, patients were put into three groups: anosmia, hyposmia, and no OD (control). Of the patient cohort, 68.7% had OD, with 37% having anosmia and 29% having hyposmia. Dysgeusia was found in 44.8% of patients. As one might expect, the QoL scores of those patients with hyposmia or anosmia were lower than in those patients with no OD in all three surveys (p<0.05). The QOD-NS scores of those patients with OD lasting more than 14 days were significantly lower in all three surveys. Only 4.3% of those patients with OD had no spontaneous recovery after one month. The authors conclude that recovery of OD is quicker in those patients with hyposmia than anosmia, and permanent OD from COVID-19 infection is rare. They also mention that, for those patients with OD lasting longer than 15 days, treatment of their symptoms is beneficial to avoid long-term loss of smell. This study suggests that long-term OD are rare after COVID-19 infection, and gives an outline of the natural course of OD post COVID-19 infection, which can be a useful tool for counselling patients.

Olfactory disorders in patients with mild to moderate COVID-19: spontaneous recovery in one-month follow up.
Inan S, Ozer F, Erbek SS, et al.
B-ENT
2021;17(1):18-23.