RESUMO
BACKGROUND: A nasally applied cellulose powder is increasingly used in many countries as a remedy for allergic rhinitis. In 2009, a 4-week study in birch pollen-allergic children showed a reduction in nasal symptoms. The best effect occurred on days with lower pollen counts. The present study in grass pollen-allergic adults used the same basic design. METHODS: In May 2013, a double-blind, placebo-controlled study was conducted in 108 patients with allergic rhinitis due to grass pollen (18-40 years of age). SMS on mobile phones were used as reminders of treatment and reporting of symptom scores. RESULTS: We found significant reductions in severity scores for sneezing, runny nose, stuffy nose and symptoms from eyes and lower airways, both separately and together (all p < 0.001). Reflective opinion of effect and guess on treatment at follow-up visits (both p < 0.001) confirmed a high efficacy. No clinically significant adverse effects were reported. CONCLUSIONS: The product provided significant protection against all seasonal allergic rhinitis symptoms from both upper and lower airways during the grass pollen season in an adult population. The magnitude and scope of efficacy support the use of the product as an early choice in the treatment of allergic rhinitis.