RESUMO
BACKGROUND: Allergic rhinitis is commonly treated with antihistamines. Monitoring improvement of airway inflammation noninvasively using nasal nitric oxide (nNO) would be clinically useful. To determine the anti-inflammatory effect of oral levocetirizine dihydrochloride (LC), we measured nNO and nasal eosinophils (nEos) in perennial allergic rhinitis (PAR) subjects. METHODS: A randomized double-blind placebo-controlled crossover design was used. Inclusion criteria consisted of subjects having a PAR history, exam and diary scores consistent with active symptoms, and positive skin testing. Subjects taking allergy medications 1 month before the study were not enrolled. After consenting, 31 subjects (24 female subjects; mean age, 29 years) were randomized to either oral LC (5 mg) or matching placebo for 2 weeks. After 2 week washout, subjects started the other 2-week treatment. At each visit, nNO was measured by aspiration at each nare using a nasal kit from NIOX (Aerocrine, Sweden) in parts per billion; nEos was collected from nasal smears and measured by microscopy using the scoring system (0-4+) and symptoms were self-reported using the allergic Rhinitis Quality of Life Questionnaire (RQLQ). Daily allergy symptom scores (total symptom score [TSS] 4) were collected at each visit. RESULTS: During LC, mean baseline nNO was 807 ± 317 parts per billion (ppb; left) and 831 ± 332 ppb (right) and decreased significantly to 688 ± 266 ppb and 702 ± 286 ppb, respectively (p < 0.05). No significance was found during placebo treatment (778 ± 270 ppb, 808 ± 299 ppb to 802 ± 271 ppb, 813 ± 273 ppb). The mean nNO change was also significant compared with placebo (-125 ppb versus +14 ppb; p < 0.05). There was a significant decrease in nEos with LC compared with placebo (3.1-2.5 versus 2.9-2.6; p < 0.05). RQLQ scores were significantly improved with LC only. In TSS-4 scoring, a trend toward improvement during LC and significant worsening during placebo was found. Baseline nNO predicted changes in nasal eosinophils (nEos) and RQLQ. CONCLUSION: We showed that oral LC therapy decreased objective markers of rhinitis inflammation, nNO and nEos, in patients with PAR. Improvement in symptom scoring was also found with LC treatment.