Effect of H-1 and H-2 antagonists on nasal symptoms and mediator release in atopic patients after nasal allergen challenge during the pollen season

During the pollen season, quantitative determination of the chemical mediators and eosinophil count was performed in 16 patients with hay fever after nasal allergen challenge (NAC). The aim of this study was objectively to assess the effect of H-1 and of a combination of H-1 and H-2 antagonists on nasal symptoms, mediator release, and eosinophil count during an allergic reaction. NAC was performed at baseline (V1), 2 weeks after treatment with cetirizine 10 mg/day (V2), and after a combined therapy with cetirizine 10 mg and cimetidine 800 mg a day during the following week (V3). Results showed a significant (p < 0.05 or p < 0.01) relief of nasal symptoms such as: itching, sneezing, rhinorrhea and congestion, and of objective parameter such as: reduction of the number of sneezes after NAC at V2 and V3. Neither H-1 antagonist nor a combination of H-1 and H-2 antagonists showed any effect on eosinophilia and ECP concentration caused by natural allergen exposure, nor on histamine and tryptase release immediately after NAC. When a combination of H-1 and H-2 antagonists was administered significant reduction of the nasal airway resistance and increase of the nasal air flow were demonstrated.