Investigation of the relationship between anosmia in patients with COVID-19 and allergic rhinitis and eosinophil levels

Abstract

Anosmia is a common symptom of COVID-19 infection. In our study, we aimed to investigate the relationship between allergic rhinitis and eosinophil levels in patients who developed anosmia after COVID-19 infection. Patients who had experienced COVID-19 infection and subsequently developed anosmia were included in the study group, while those who had experienced COVID-19 infection but did not develop anosmia were included in the control group. The patients' allergy histories and eosinophil levels were retrospectively analyzed. Our study revealed a significant difference in eosinophil levels between patients with and without anosmia (p<0.05). Additionally, among 55 patients with pre-existing allergic rhinitis, 43 (78.2%) had normal or high eosinophil levels. There was no significant relationship found between age, gender, the most common presenting symptom, hospitalization status, presence of allergic rhinitis and asthma before COVID-19 and increase in allergic symptoms after COVID-19 infection, in patients with and without anosmia.While we did not find a relationship between the presence of allergic rhinitis and the development of anosmia, our study did show that eosinopenia is more pronounced in patients with anosmia. Furthermore, it has been suggested that eosinopenia may not be a suitable marker for patients with allergic symptoms before COVID-19, as these patients may have normal or high eosinophil levels.