A comparative study of eosinophil count in nasal smear and peripheral blood smear in allergic and non-allergic rhinitis patients

Abstract

Background: Allergic rhinitis is mediated by an immunoglobulin E (IgE) Type-1 inflammatory disorder of the nasal membrane following exposure to an allergen, characterized by the presence of one or more symptoms that include sneezing, itching, nasal congestion, and rhinorrhea. Mucosal inflammation in allergic rhinitis is characterized by tissue eosinophilia. The present study has been designed to verify the specificity and sensitivity of nasal smears in the diagnosis of allergic rhinitis compared to the gold standard of peripheral blood smears. Methods: Our study was conducted on 90 patients with allergic rhinitis and 90 age-sex-matched controls of non-allergic rhinitis. Smears were obtained from nasal secretions and peripheral blood. Smears from both groups were fixed and stained, and studied under light microscopy. Results: In allergic and non-allergic rhinitis, the sensitivity, specificity, positive predictive value, and negative predictive value of nasal smear tests were 76.66%, 87.77%, 86.25%, and 79%, respectively. The present study documented the premise that a significant difference in nasal smear and peripheral blood smear eosinophil count exists in patients of allergic rhinitis as compared to the counts of normal health adults, exemplifying the fact that nasal eosinophilia could act as an informative first tool of point of contact for the provisional diagnosis of allergic rhinitis. Conclusion: Nasal smear eosinophil cytology is a simple, economical, and semi-invasive procedure that could be used as a diagnostic and prognostic test for patients suffering from allergic rhinitis.