Childhood asthma can be caused by many factors, including allergens, cigarette smoke, air pollution, or infections. Symptoms include wheezing, shortness of breath, chest tightness, and coughing. Wheezing illnesses are common during the first several years of life, and continuous wheezing, or recurrent intermittent wheezing, may be an indicator of asthma. Recurrent intermittent wheezing can also lead to breathing difficulties, sleep disturbances, and severe exacerbations that result in emergency department visits, hospitalizations, or even death. The Prevention of Early Asthma in Kids (PEAK) and Acute Intervention Management Strategies (AIMS) studies, both of which are part of the Childhood Asthma Research and Education (CARE) Network, as well as several other studies, have identified therapies that may improve recurrent wheezing in young children. This study will compare the safety and effectiveness of two treatment regimens—low doses of ICS taken on a daily basis versus higher doses of ICS taken only during respiratory tract illnesses—at improving recurrent wheezing in toddlers. Study researchers will also identify individual characteristics (e.g., age, gender, family history of asthma and allergies, the degree of allergy, genetics) that may be associated with treatment response. Lastly, the relationship of virus infections to respiratory illnesses, wheezing episodes, and response to study treatments will also be studied.