THE INTRANASAL Schirmer test (INSCH), adapted from the established ophthalmological Schirmer test for tear fluid measurement, has emerged as a valuable diagnostic instrument in the evaluation of nasal secretions. Traditionally underutilised, recent studies highlight its potential in allergology, particularly during nasal provocation testing (NPT).
NPT involves the direct application of allergens to the nasal mucosa to confirm allergic rhinitis in cases where skin prick tests or specific IgE results are inconclusive. However, NPT alone can suffer from low sensitivity and often relies on subjective symptom reporting. While anterior rhinomanometry (aRMM) is the current objective standard, it is resource-intensive and requires significant patient cooperation.
This study investigates the role of INSCH as a supportive or alternative tool to aRMM in NPT. By measuring nasal secretion using filter papers before and after allergen exposure, the INSCH offers a quick and inexpensive method to quantify rhinorrhea. Findings showed that patients with a positive allergic response had significantly increased nasal secretion, measured as greater wetting length, on the allergen-provoked side. A cut-off of 2.75 mm wetting distance increase achieved 81.8% sensitivity and 71.4% specificity.
Unlike aRMM, INSCH is simple to apply, well-tolerated by patients, and does not require specialist training. Although it lacks aRMM’s specificity, its cost-effectiveness and ease of use make it highly practical for routine clinical use. The study suggests that combining INSCH with aRMM or symptom scores could strengthen diagnostic objectivity for allergic rhinitis and even support diagnosis of local allergic rhinitis (LAR).
While further research is needed, especially with larger cohorts and additional controls, the INSCH shows strong potential as both a diagnostic and therapeutic monitoring tool. Its implementation could streamline allergy diagnostics, reduce costs, and improve patient care by providing a reliable, objective measure of nasal secretion.
Reference
von der Lage P et al. Intranasal Schirmer test: a useful diagnostic tool in nasal allergen provocation testing. Ann Allergy Asthma Immunol. 2025;DOI:10.1016/j.anai.2025.05.012.
