CARE Network Maintenance Versus Intermittent Inhaled Steroids in Wheezing Toddlers (MIST)

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. This study will enroll children between 12 and 53 months of age who have experienced episodes of wheezing or coughing in the year before study entry, with at least one episode that required one of the following: oral steroids, an urgent unscheduled medical visit, an emergency room visit, or hospitalization. This study will begin with a 2-week evaluation period during which potential participants will receive placebo once a day. Parents will document their child's asthma symptoms and medication use in a daily diary. Next, at a baseline study visit, eligible participants will be randomly assigned to one of the following two 12-month treatment groups: * Group 1 participants will receive a low dose of ICS once a day at night, except during respiratory tract illnesses. During a respiratory tract illness, participants will receive placebo each morning and a low dose of ICS each night for 7 days. * Group 2 participants will receive a high dose of ICS twice a day for 7 days during each respiratory illness and placebo once a day at night at all other times. Throughout the 12 months of treatment, all participants will receive albuterol to treat respiratory symptoms and prednisolone if asthma symptoms worsen. Parents will be given an action plan to help manage their child's symptoms, and during respiratory illnesses, parents will contact study researchers to determine the best treatment plan. Study visits will occur at baseline and Weeks 4, 12, 20, 28, 36, 44, and 52. Participants' parents will take part in scheduled telephone interviews one month after each clinic visit to provide information on their child's asthma symptoms, study medication use, and health problems. Most study visits will include a physical exam and lung function testing. At select study visits, the following will occur: allergy skin testing, blood collection, nasal mucus sampling, and parent questionnaires to assess asthma, quality of life, and environmental factors. A portion of the participants' blood will undergo genetic analysis; a blood collection from parents for genetic analysis will be optional. Throughout the treatment period, participants' parents will record asthma symptoms and medication usage in a daily diary.