Patient description: The patient is a 15-year-old boy with asthma diagnosed a year ago. He presents with shortness of breath, chest tightening and cough. According to his mother, he didn't respond to the usual corticosteroid inhaler. He was admitted to the emergency department with diagnosis of severe asthma exacerbation. He is a candidate for general corticosteroid therapy. Spirometry revealed a forced expiratory volume in the first second (FEV1) of 60% of the predicted. His past medical history is non-significant. His family history is significant for asthma in his mother and his uncle. He used to be treated with combination of inhaled corticosteroids and Zafirlukast.

Clinical trial eligibility criteria: eligible ages (years): 6.0-18.0,  Asthma Able to perform reproducible spirometry according to American Thoracic Society (ATS) History of asthma symptoms that are adequately controlled in the 4 weeks prior to study entry, and meets at least one of the following 1. History of mild persistent asthma symptoms (on average greater than 2 days per week with symptoms or albuterol use for symptoms or greater than 2 night-time awakenings per month during the year prior to study entry) and has been treated with a single-controller inhaled corticosteroid (ICS) dose less than or equal to 160 mcg per day of a beclomethasone-equivalent or a leukotriene receptor antagonist (LTRA) (in an age-appropriate dose) for the 4 weeks prior to study entry; individuals treated with a combination controller therapy (e.g. ICS+LTRA or ICS+long-acting beta-agonist (LABA)) in the past 8 weeks will not be eligible 2. Not currently being treated with ICS, a history of mild persistent asthma, and 1 to 2 exacerbations in the year prior to study entry (but none in the 3 months prior to study entry) Forced expiratory volume in one second (FEV1) reversibility of greater than or equal to 12% following bronchodilator administration (4 puffs); individuals who do not meet this requirement may qualify for enrollment if their methacholine provocative concentration at 20% (PC20) is less than or equal to 12.5 milligrams per milliliter (mg/ml) History of clinical varicella or varicella vaccine; individuals needing the vaccine may receive it from their primary care physician prior to study entry Ability of parent to provide informed consent; verbal assent must be obtained from children less than 7 years of age and written assent must be obtained from children between 7 and 18 years of age If female, willing to use an effective form of contraception Participants will be eligible for the 44 weeks of treatment if, after the 4-week screening period, their asthma remains controlled, and they demonstrate at least 80% predicted pre-bronchodilator FEV1. Participants must meet ALL of the stated below during the 8-week screening period to continue in the study Meets the definition of acceptable asthma control, which is NOT having one or more of the following during ANY 2-week period: 1. On average, on more than 2 days per week, experiences one or more of the following: 1. Diary-reported symptoms 2. The use of inhaled bronchodilator (not including pre-exercise) 3. Peak flows in the yellow zone (less than 80% of personal best defined as based on peak expiratory flow (PEF) value obtained at study visit 1 2. More than 1 night-time awakening due to asthma Demonstrates adherence with taking study medications (at least 75% of scheduled doses), rescue medications (using both rescue inhalers for at least 75% of rescue doses), and completing patient diaries (at least 75% of days) Pre-bronchodilator FEV1 greater than or equal to 80% predicted at study visits 2 and 3 Agrees to not use a spacer with beclomethasone/placebo study and rescue medications NOTE: In January 2008, the Data and Safety Monitoring Board (DSMB) approved changes in the TREXA by which neither FEV1 reversibility ≥ 12% nor a participant's methacholine PC20 ≤ 12.5 mg/ml were required for randomization  Corticosteroid treatment for any condition prior to study entry within the following defined timepoints: 1. Oral Use within 2-week period of the screening visit 2. Injectable Use within 2-week period of the screening visit 3. Nasal corticosteroids may be used at any time during the study at the discretion of the study investigator or primary care physician Current or prior use of medications known to significantly interact with corticosteroid disposition (within a 2-week period of study visit 1), including but not limited to carbamazepine, erythromycin or other macrolide antibiotics, phenobarbital, phenytoin, rifampin, or ketoconazole Pre-bronchodilator FEV1 less than 60% predicted at study visit 1 Any hospitalization for asthma in the year prior to study entry Presence of chronic or active lung disease other than asthma Significant medical illness other than asthma, including thyroid disease, diabetes mellitus, Cushing's disease, Addison's disease, hepatic disease, or concurrent medical problems that could require oral corticosteroids during the study History of cataracts, glaucoma, or any other medical disorder associated with an adverse effect to corticosteroids Any asthma exacerbation in the past 3 months or more than 2 in the past year