Background: Rhinorrhea is a key symptom of allergic rhinitis and this disease feature is reduced by antihistamine treatment. The nasal output of fluid in allergic rhinitis is associated with luminal appearance of bioactive molecules emanating from the microcirculation as well as the secretory apparatus.
Objective: In the present study, we examined the effects of antihistamine treatment on nasal symptoms and output of mucinous secretions and plasma.
Methods: Desloratadine (5 mg) was administered orally once daily for 5 days in a placebo-controlled, crossover design to 24 patients with allergic rhinitis. Nasal challenges with diluent and allergen (100 to 10,000 SQ-U) were carried out on day 5 of the treatment. The nasal mucosa was lavaged with saline, and symptoms were scored 10 minutes after each allergen challenge and 1 to 4 hours after the challenge series. Nasal lavage fluid levels of fucose and alpha2-macroglobulin were determined as indices of mucinous secretion and plasma exudation, respectively.
Results: The allergen challenges produced nasal symptoms, including rhinorrhea, and increased nasal output of fucose and alpha2-macroglobulin. Desloratadine reduced the nasal symptoms (P < 0.05 to 0.001) and output of fucose (P < 0.05 at 100 and 1,000 SQ-U) and alpha2-macroglobulin (P < 0.05 at 1,000 SQ-U). In both treatment groups, symptoms and nasal lavage fluid levels of fucose and alpha2-macroglobulin returned toward prechallenge levels 1 to 4 hours after the allergen challenge series.
Conclusion: We conclude that the antihistamine desloratadine, in addition to a symptom-reducing effect, also reduces acute allergen challenge-induced mucinous secretion and plasma exudation in allergic rhinitis.