Inhaled beclomethasone dipropionate (BDP) prevents seasonal changes in atopic asthmatics

Inhaled corticosteroids are most effective drugs currently available for the treatment of bronchial asthma. They have been shown to reduce airway inflammation and hyperresponsiveness. The aim of this study was to assess the preventive effect of inhaled steroid therapy in seasonal asthma. In a double-blind study, two groups of 10 allergic asthmatics were randomly assigned to receive inhaled beclomethasone dipropionate (BDP), 500 micrograms b.i.d., or a matched placebo, two puffs b.i.d. The patients used inhaled salbutamol as needed. At the beginning of the study, and every month between February and June, the following parameters were assessed: lung function (forced expiratory volume in one second (FEV1); airway responsiveness (provocative dose of methacholine producing a 20% fall in forced expiratory volume in one second (PD20)), serum eosinophil cationic protein (ECP); and blood eosinophil count. All subjects recorded daily asthma symptoms, beta 2-agonist consumption and peak expiratory flow (PEF) values. In the placebo group, all parameters except FEV1 worsened significantly during the pollen season compared with preseasonal values (p < 0.001). BDP produced complete protection, although a slight change from baseline was found for symptom score (p < 0.01), beta 2-agonist consumption (p < 0.01), and eosinophil number (p < 0.05) in May, when the pollen load was highest. These data provide evidence that beclomethasone dipropionate treatment is able to inhibit the seasonal changes occurring during natural exposure in asthmatics. This preventive effect is probably due to the anti-inflammatory action of beclamethasone dipropionate, as documented by its effect on serum markers of airway inflammation.