Comparative analyses of post-infectious olfactory dysfunction between COVID-19 and non-COVID-19 cases

Area of Science:

• Otolaryngology
• Infectious Diseases
• Neurology

Background:

• Post-infectious olfactory dysfunction (PIOD) can be associated with various viral infections.
• Distinguishing between COVID-19-associated and non-COVID-19-associated olfactory dysfunction is crucial for understanding disease characteristics and treatment outcomes.

Purpose of the Study:

• To compare the demographic and clinical characteristics of patients with COVID-19-associated olfactory dysfunction (OD) versus non-COVID-19-associated OD.
• To analyze differences in olfactory function test results and treatment responses between the two groups.

Main Methods:

• Analysis of demographic and clinical data from 169 patients with PIOD.
• Comparison of olfactory questionnaire and olfactory function test results (TDI, discrimination, identification, threshold) between COVID-19 and non-COVID-19 groups.
• Assessment of treatment outcomes for olfactory dysfunction.

Main Results:

• The COVID-19 group (99 patients) was younger, more frequently male, and reported higher rates of parosmia compared to the non-COVID-19 group (70 patients).
• Initial olfactory function tests showed significantly higher TDI, discrimination, and identification scores in the COVID-19 group.
• Following treatment, odor detection threshold improved in the COVID-19 group, while odor identification improved in the non-COVID-19 group.

Conclusions:

• COVID-19-associated OD presents distinct characteristics, including younger age, male predominance, higher parosmia incidence, and better initial olfactory function compared to non-COVID-19 OD.
• Treatment strategies may need to be tailored, as odor detection improves with treatment in COVID-19-related cases, whereas odor identification shows improvement in non-COVID-19-related cases.