Acoustic Rhinometry in the Evaluation of Nasal Lysine Aspirin Challenge

Background: Nasal lysine aspirin (Lys-ASA) challenge is an alternative to oral and bronchial challenges in the diagnosis of hypersensitivity to acetylsalicylic acid (ASA) and other non-steroid anti-inflammatory drugs (NSAIDs). The aim of the study was to evaluate the sensitivity and specificity of acoustic rhinometry as an objective method of evaluation of nasal Lys-ASA challenge. Material and methods: We enrolled 20 patients with ASA-induced asthma confirmed by oral challenge (ASA-S group), 5 patients with allergic rhinitis without hypersensitivity to NSAIDs, and 5 healthy individuals (ASA-NS group). All the subjects underwent challenge with placebo (0.9% NaCl) or 14.4 mg of Lys-ASA applied in a spray into both nostrils (total dose: 16 mg of ASA). Measurements of nasal volume bilaterally were performed with an acoustic rhinometer before and 1, 2, 4, and 24 hours after the challenge. For further calculations we used the sum of both nasal volumes at 2 to 5 cm from the nostrils. Results: The mean total nasal volume in the AIA group before and 1, 2, 4, and 24 hours after the challenge was 7.75, 6.21, 7.11, 7.12, and 7.24 cm³ following placebo, respectively, and 7.24, 5.77, 6.31, 6.27, and 6.98 cm³ following Lys-ASA, respectively (p = 0.048 and p = 0.02 at 2 and 4 hours, Lys-ASA vs. placebo, Wilcoxon test). With the cutoff value of nasal volume reduction of 10%, the test sensitivity was 70%, the specificity was 60%, the positive predictive value was 77.78%, and the negative predictive value was 50% at 1 hour after the challenge. Conclusions: Acoustic rhinometry with the measurement of nasal volume at 2 to 5 cm from the nostrils proved insufficiently sensitive or specific to be used as the sole method for evaluation of nasal Lys-ASA challenge.