Nasal treatment with a microemulsion reduces allergen challenge-induced symptoms and signs of allergic rhinitis

Conclusions. Intranasal microemulsion treatment can attenuate allergen challenge-induced nasal symptoms and plasma exudation in allergic rhinitis. We hypothesize that the mechanism of action involves modification of the allergen-mucosa interaction. The present observation suggests a novel principle for prevention in allergic rhinitis. Objective. To evaluate a specific microemulsion as a treatment for allergic rhinitis in an acute allergen challenge model. Patients and methods. Patients with allergic rhinitis were examined out of the pollen season. Treatment with a single dose of a specific microemulsion was given in a single-blind, placebo-controlled, and crossover design using a nasal pool device. Nasal allergen challenges were carried out and symptoms of allergic rhinitis were scored. Furthermore, nasal lavages were performed and levels of the plasma protein alpha(2)-macroglobulin were measured as an index of exudative inflammation. Results. The allergen challenges produced significant increases in nasal symptoms (p = 0.007) and in nasal lavage fluid levels of alpha(2)-macroglobulin (p = 0.008). The challenge-induced symptoms as well as the plasma exudation were attenuated by treatment with the microemulsion (p = 0.016 and 0.012, respectively, compared with placebo).