Effect of inhalation of corticosteroids on exercise induced asthma: Randomised double blind crossover study of budesonide in asthmatic children

Abstract

Budesonide given by inhalation for three weeks afforded significant protection against exercise induced asthma in most children without appreciable suppression of adrenal function. Improvement in baseline airway function cannot explain the effect of budesonide on exercise induced asthma. Normal 24 hour urinary free cortisol excretion cannot exclude more subtle degrees of adrenal suppression. The present results and the finding that the immediate reaction induced by allergen was blocked after a week's treatment with prednisone show that regular steroid treatment attenuates some immediate asthmatic reactions. The pathogenesis of exercise induced asthma and the precise modes of action of steroids, however, are incompletely understood. It is generally accepted that the airway cooling that occurs during exercise initiates the bronchoconstriction, but the mechanism is unknown. The decrease in bronchial reactivity during steroid treatment might result from decreased mucosal inflammation, reflex activity, or mediator release.