Background Allergic rhinitis is characterized by an IgE-dependent inflammation. Nasal obstruction is related to allergic inflammation. Some antihistamines have been demonstrated to be capable of improving this nasal symptom.
Objective The aim of this pilot study was to evaluate nasal symptoms, nasal airflow, inflammatory cells, and cytokine pattern in patients with seasonal allergic rhinitis (SAR), before and after treatment with levocetirizine, desloratadine, or placebo.
Methods Thirty patients with SAR were evaluated, 27 males and three females (mean age 26.9±5.4 years). All of them received levocetirizine (5 mg/day), desloratadine (5 mg/day), or placebo for 2 weeks. The study was double-blind, parallel-group, placebo-controlled, and randomized. Total symptom score (TSS) (including: rhinorrhea, nasal itching, sneezing, and nasal obstruction) was assessed before and after treatment. Rhinomanometry, nasal lavage, and nasal scraping were performed in all subjects before and after treatment. Inflammatory cells were counted by conventional staining; IL-4 and IL-8 were measured by immunoassay on fluids recovered from nasal lavage.
Results Levocetirizine treatment induced significant symptom relief (P=0.0009) and improved nasal airflow (P=0.038). Desloratadine also relieved TSS (P=0.01), but did not affect nasal airflow. Levocetirizine significantly reduced eosinophils (P=0.029), neutrophils (P=0.005), IL-4 (P=0.041), and IL-8 (P=0.02), whereas desloratadine diminished IL-4 only (P=0.044). Placebo treatment did not significantly affect any evaluated parameters.
Conclusions This pilot study demonstrates the effectiveness of levocetirizine in: (i) relieving nasal symptoms, (ii) improving nasal airflow, (iii) reducing leucocyte infiltration, and (iv) diminishing cytokine levels. These findings are the first evidence of the effectiveness of levocetirizine in SAR.