LAR is characterized by chronic rhinitis with a localized nasal allergic response to allergens in the absence of systemic IgE-mediated disease assessed by SPT or specific serum IgE level. NPT is the gold standard for the diagnosis of LAR. Nasal eosinophilia is a known inflammatory marker in allergic rhinitis.

Researchers did this study to determine the applicability of nasal eosinophilia as a diagnostic tool for LAR. Researchers recruited forty-eight perennial NAR patients with SPT negative. Nasal cytology analysis was performed. NPTs with three allergens were performed to diagnose LAR. LAR was diagnosed in 41.6% of the NAR patients. Nasal eosinophilia was found in 58% of the NAR patients. The sensitivity of nasal eosinophilia for diagnosing LAR was 80%, the specificity was 57.14%, the positive predictive value was 57.14%, and the negative predictive value was 80%. The most common allergen of LAR was mixed mites.

The study concluded that nasal eosinophilia on nasal cytology was a useful screening tool for diagnosing LAR because of its high sensitivity and simplicity of the procedure. Unfortunately, the low specificity of nasal eosinophilia makes the NPT necessary for confirmation of LAR.

Reference: https://journals.sagepub.com/doi/full/10.1177/1945892419850926