A Cross-Sectional Observational Study to Determine the Diagnostic Utility of Nasal Smear Eosinophilia and Serum Immunoglobulin E (IgE) Level in Allergic Rhinitis in Adult Population

Background: Allergic rhinitis (AR) is an IgE-mediated inflammation of nasal mucosa triggered by allergen exposure, affecting 10-40% of global population. Diagnosis relies on clinical history, symptoms like rhinorrhoea, nasal itching, sneezing, & pale bluish mucosa, & tests such nasal smear eosinophilia and elevated serum IgE. This study aimed to evaluate the diagnostic utility of these markers in clinically confirmed AR cases and assess nasal smear eosinophilia severity correlates with symptom severity. Materials & Methods:100 consenting adults (18-75 years) attending the ENT department were enrolled & divided into 50 cases (AR patients) and 50 age & sex matched controls. Nasal smears were collected from both nostrils, fixed, and stained with Leishman and H&E stains. Slides were examined under 1000X magnification; >5 eosinophils in 3-5 fields or 20-30 cells single finding indicated positivity, graded as mild, moderate, & severe. Serum IgE was measured via chemiluminescent immunoassay. Results: Mean age was 39.78?15.15 years (range 18-75). Cases had 46% males, 54% females. Mean IgE level was 364.14?339.42 IU/ml in group I vs. 100.62?34.60 in group II (p<0.001). The mean nasal smear eosinophil count was 14.56?17.43 in group I & and 1.32?8.21 in group II (p<0.001). Nasal smear eosinophilia showed 81.3% positive predictive value at >0.3/HPF. Symptom severity correlated well with eosinophilia grading. Conclusions: Nasal smear eosinophilia and serum IgE aid AR diagnosis, with serum IgE offering better sensitivity and comparable specificity. Nasal eosinophilia is highly specific and links to symptom severity, supporting its routine use.