Assessment of the allergic reaction in seasonal rhinitis: Acoustic rhinometry is a sensitive and objective method

Background Seasonal allergic rhinitis constitutes an excellent in vivo model of an allergic mucosal inflammatory reaction. This offers the opportunity of studying the fundamentals of allergic inflammation in addition to improvement of knowledge on the basal pathophysiological mechanisms of the disease, So far, monitoring methods of disease activity and treatment efficacy have mainly been based upon subjective assessments, illustrating the impact of introducing reliable objective methods. Objective To investigate the allergic inflammatory reaction of seasonal rhinitis through different objective methods and evaluate these as indicators of disease activity and treatment efficacy. Methods Functional parameters, i.e. acoustic rhinometry and nasal metacholine challenge, and biological markers, i.e. blood eosinophil count, eosinophil cationic protein in serum (s-ECP) and nasal lavage fluid (n-ECP), were assessed before and at peak pollen season in 27 patients with grass pollen induced rhinitis, Patients were randomized to either nasal corticosteroid or placebo treatment and recorded nasal symptom scores. Results Acoustic rhinometry revealed a significant difference in favour of steroid treatment (P < 0.05) comparing nasal volumes before and during season. This difference primarily relied upon a decrease in the placebo group (P= 0.05). A reduction from baseline of s-ECP in the steroid group (P < 0.01) was obtained. N-ECP demonstrated a difference between treatment groups, although not significant. Symptom scores increased in all patients during the pollen season, although this was only significant in the placebo treated patients (P < 0.01). The remaining methods applied did not demonstrate further differences, either within or between treatment groups. Conclusion Our results demonstrate acoustic rhinometry to be a sensitive and objective method of assessment of nasal obstruction, Furthermore, acoustic rhinometry and s-ECP reflect the impact of nasal steroid therapy on seasonal allergic rhinitis.