Asthma is a common, serious illness among children in the United States. While a low dose of inhaled corticosteroids (ICS) may effectively control symptoms, some children may require additional medications to maintain adequate asthma control. This study compares the effectiveness of a higher dose of ICS, ICS combined with a long-acting beta-agonist (LABA) medication, and ICS combined with a leukotriene receptor antagonist (LTRA) medication at reducing the impact and severity of asthma exacerbations that occur in children with mild to moderate persistent asthma.