Exhaled nitric oxide in asthmatic children exposed to relevant allergens: effect of flunisolide.

Inhaled corticosteroids are capable of reducing the level of exhaled nitric oxide (expiratory nitric oxide fraction (FE,NO)) in asthmatic patients in a dose-dependent fashion. The aim of this study was to evaluate whether or not treatment with an inhaled steroid can prevent changes in FE,NO after the exposure to relevant allergens, following avoidance, in asthmatic children allergic to house dust mite. Thirty-two house dust mite-allergy asthmatic children were randomly allocated to treatment with inhaled flunisolide (500 microg b.i.d) or placebo and evaluated before and 2 weeks after a period of natural exposure to mite antigens. Lung function and FE,NO were evaluated. FE,NO was increased in the placebo-treated group after antigen exposure. Treatment with inhaled flunisolide prevented such increase in FE,NO (p<0.001). No change was observed in lung function parameters. Inhaled flunisolide is effective in preventing the increase in airway inflammation observed in allergic asthmatic children re-exposed to allergens.