Unveiling the allergic rhinitis puzzle: exploring the association between nasal smear eosinophilia, peripheral absolute eosinophil count and serum IgE level with allergic rhinitis severity

Abstract Background Allergic rhinitis (AR) is a global health problem that affects subjects of all ages and ethnic groups. It is one of the most common chronic conditions with a significant impact on the quality of life. The association between eosinophils and allergic diseases has been known for many years. Nasal smear cytology with moderately high sensitivity and high specificity is a valuable test for the diagnosis of allergic rhinitis. Methods A prospective study was conducted for 18 months with 64 subjects of allergic rhinitis, above 18 years of age. After taking consent, peripheral absolute eosinophil count (AEC), serum IgE level, and nasal smear eosinophilia (NSE) were assessed in each subject. The Sino nasal outcome test-10 scale was used to assess their clinical severity of AR. The individual and combined test associations were calculated and compared. The data was analyzed using SPSS software. Results AEC > 440 cells/cumm was seen in 31.25%, total serum IgE > 100 IU/ml in 78.12%, and NSE > 5% in 67.18%. There was a good association between serum IgE and NSE with the severity of the disease as isolated tests. The association of peripheral AEC with the severity of clinical score as an isolated diagnostic tool was relatively low, as 44 (68.75%) out of 64 subjects had the value of AEC within the normal range. The test positivity rate of the combination of AEC + IgE, AEC + NSE, and IgE + NSE was 79.7%, 67.2%, and 67.2%, respectively, which showed no improvement in diagnostic ability when compared to individual tests. Conclusion The young adult population is most affected, adding to the social burden. Serum IgE level is the singlebest diagnostic tool that correlates best with clinical severity, followed by NSE. No combination of tests yields better diagnostic ability than an isolated test.