There is currently significant interest in the early identification and early intervention in childhood asthma. Because of the increasing prevalence of allergy and asthma throughout the world, it is important to develop new approaches to facilitate the early diagnosis of asthma. Current asthma guidelines identify inhaled glucocorticoids as the preferred initial long-term control therapy. Although inhaled glucocorticoids clearly improve asthma control in children with mild to moderate persistent asthma, it is not clear that they can alter the natural history and progression of asthma.