Continuous antihistamine treatment controls allergic inflammation and reduces respiratory morbidity in children with mite allergy

Background: Allergic reaction is characterized by a complex inflammatory pr ocess. Some of the new antihistamines have antiallergic effects and can aff ect the inflammatory cell recruitment via adhesion molecule downregulation. We aimed to assess in a 12-month study whether continuous treatment with a n antihistamine (terfenadine) can reduce respiratory symptoms and local inf lammation in children with mite allergy. Methods: The study was double-blind and placebo-controlled: it involved two parallel groups of children suffering from rhinoconjunctivitis and/or mild intermittent asthma due to mite allergy. They received either terfenadine (1 mg/kg per body weight per day) or placebo for 1 year. Nasal, conjunctiva l, and bronchial symptoms were recorded by diary cards; at each of the prog rammed control visits, a nasal scraping for inflammatory cells and ICAM-1 w as performed. Some additional clinical parameters were also recorded: days of school absence, extra visits for acute respiratory symptoms, and days of hospital admission. Results: Only children treated with terfenadine achieved significant contro l of symptoms (P<0.05 in 8 out of 12 months) and allergic inflammation, as shown by inflammatory cell infiltrate and ICAM-1 expression at nasal level (P<0.001), and had significantly fewer extra visits and school absences tha n the placebo group (P<0.03). No side-effects were reported in either group . Conclusions: The present study demonstrates that continuous terfenadine tre atment (1 mg/kg body weight per day) could decrease respiratory symptoms an d allergic inflammation, and it had an additional antiallergic effect in re ducing ICAM-1 expression on nasal epithelial cells; Therefore, the present results confirm the efficacy of a long-term therapeutic strategy in control ling allergic inflammation.