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The following is a summary of “Intranasal Schirmer Test: A Useful Diagnostic Tool in Nasal Allergen Provocation Testing,” published in the May 2025 issue of Annals of Allergy, Asthma & Immunology by Lage et al. 

Researchers conducted a retrospective study to evaluate changes in nasal secretion using the intranasal Schirmer test (INSCH) during direct nasal allergen provocation (NPT).  

They assessed individuals who underwent allergy diagnostics with NPT and anterior rhinomanometry (aRMM). Schirmer filter paper was applied bilaterally to the nasal septum before and after allergen exposure to measure secretion. Each participant completed the [sinonasal outcome test 22 (SNOT-22)]. The difference in wetting length was analyzed before and after provocation, and a cut-off value for allergic rhinitis was calculated.  

The results showed that 25 participants were included in both the allergy diagnostic and control groups. Individuals with a positive NPT had significantly greater nasal secretion on the provoked side, with a mean difference of 13.95 mm (P= 0.01). The increase in wetting length after provocation produced an area under the curve (AUC) of 0.814. A threshold of 2.75 mm increase was determined using the Youden index (Youden index = 0.532), yielding 81.8% sensitivity and 71.4% specificity. Participants undergoing allergy diagnostics scored 25.04 points higher than controls on the SNOT-22 (P< 0.001).  

Investigators concluded that the INSCH offered a simple and low-cost approach to evaluate nasal secretion changes and could enhance allergy diagnostics, especially in cases with inconclusive NPT results. 

Source: annallergy.org/article/S1081-1206(25)00237-6/fulltext