Investigation of olfactory disorders in patients with post-COVID fatigue syndrome

Introduction Early data from the corona pandemic shows that a large number of patients with COVID-19 infection suffered from olfactory disorders (prevalence 19-86%), which usually normalized within 1-2 months. Some patients develop a post-COVID syndrome (PCS) with marked fatigue after COVID-19 disease. So far, there is a lack of quantitative rhinological data on olfactory function in patients with post-COVID fatigue. The aim of the following study was to investigate the frequency and severity of olfactory disorders in patients with PCS-related fatigue.

Methods Adult patients with fatigue symptoms ≥3 months after COVID-19 disease were included in a real life study. A COVID-19 infection was detected by means of a PCR test. Olfactory disorders were analyzed using the age-standardized extended sniffin’ stick test (threshold, discrimination and identification (SDI)). The degree of impairment due to fatigue was assessed using the Bell score (score 0-100). A Bell score of 10 means severe symptoms even when resting, confining patients mostly to bed and a high score of 100 means a normal level of activity.

Results On average, patients presented themselves in the post-COVID consultation 10 months after infection (min 3 months, max 25 months). Of 62 patients (49 f, 13 m, Ø 47 y, min 25 y, max 68 y), 81% showed normosmia (39 f, 11 m, Ø 45 y, Ø Bell score 48), 16% hyposmia (9 f, 1 m , Ø 54 y, Ø Bell score 44) and 3% anosmia (1 female, 1 m, Ø 54 y, Ø Bell score 50). The Bell score did not differ in the subgroups normosmia, hyposmia and anosmia.

Conclusions In PCS patients, the degree of disability due to fatigue seems to be independent of the severity of the olfactory disorder.

Publication History

Article published online:
12 May 2023