Nasal and ocular responses after specific and nonspecific nasal challenges in seasonal allergic rhinitis

Abstract Background Different nasal challenges induce neural and immune response leading to nasal and ocular symptoms in patients with seasonal allergic rhinitis (SAR). The release of neural mediators from nasal mucosa and conjunctiva after no-specific challenges in patients with SAR remains unknown. Objectives To compare the release of mediators from the nose and conjunctiva with symptoms after different nasal challenges in patients with SAR. Methods Three types of consecutive nasal challenges were performed outside the pollen season in 25 patients with SAR. Challenges consisted of 500 biological units (BU) of allergen, 80 μg of histamine, and 1 mL of 2% hypertonic saline per nostril, within 24-hour and 72-hour intervals, respectively. Before and 15 minutes after challenges, evaluation of symptoms was performed with a visual analog scale. Concentrations of tryptase, eosinophil cationic protein in nasal lavages after 15 minutes, and substance P in tears after 5 minutes were measured with enzyme immunoassays. Results Concentrations of substance P in tears were significantly higher after nonspecific challenges. Substance P concentration in tears significantly correlated with eye itchiness after histamine and hypertonic saline and with tearing after allergen. Ocular symptoms correlated significantly with tryptase concentration in nasal lavage collected 15 minutes after allergen challenge. There is a significant correlation in tear volume comparing different nasal challenges. Conclusions Nasal challenges with allergen, histamine, or irritants outside the pollen season induce a significant increase in nasal and ocular symptoms in patients with SAR. Interaction of the early-phase response and neurogenic inflammation define the pattern and severity of eye symptoms.