Background: Some second-generation antihistamines have anti-inflammatory activities, but the clinical relevance of this property is still unclear.
Objective: The aim of our study was to investigate the effects of azelastine when administered during the early-phase reaction.
Methods: This investigation was designed as a randomized, placebo-controlled, double-blind, parallel-group study. Clinical and inflammatory events were evaluated after a single dose of azelastine eyedrops or placebo was administered 30 minutes after an allergen-specific conjunctival challenge. Twenty outpatients with allergic rhinoconjunctivitis attributable to Parietaria judaica were enrolled in the study outside the pollen season. Patients were evaluated at baseline, after allergen challenge (at 30 minutes), and after administration of azelastine (at 30 minutes and at 6 hours). The following variables were evaluated: hyperemia, lacrimation, itching, eyelid swelling, number of inflammatory cells (neutrophils, eosinophils, monocytes, and lymphocytes), and intercellular adhesion molecule-1 expression on conjunctival epithelial cells.
Results: Azelastine, in comparison to placebo, significantly reduced symptom scores, number of inflammatory cells, and intercellular adhesion molecule-1 expression during the early- and late-phase reaction.
Conclusions: The ability of azelastine to reduce symptoms and inflammation during an ongoing allergic reaction can be considered concrete and convincing proof of a clinically relevant anti-inflammatory activity.