Determinants Of Oral Corticosteroid Responsiveness in Wheezing Asthmatic Youth

Inclusion Criteria: * Subject will be eligible if he/she: 1. is aged 1 to 17 years, 2. has not received any oral, IM or IV corticosteroid within the last 5 days? 3. Presents to the hospital emergency department with an acute episode of cough, wheezing and/or dyspnea? 4. Has asthma as defined as one or more of the following 6 criteria: (i) prior diagnosis of asthma made by a physician; OR (ii) prior documented episode of acute cough, wheezing and/or dyspnea with significant response to inhaled β2-agonists or to oral corticosteroids; OR (iii) in a child aged \<2 years, 3 or more episodes of cough, wheezing and/or dyspnea, including the index visit; OR (iv) previous lung function tests showing significant reversibility post-bronchodilation (≥12% FEV1 or ≥25% Rrs at 4 to 8 Hz); OR (v) a positive provocation test (PC20 ≤8 mg/mL or Provocation Dose (to increase Rrs by 50% or more (PD50) ≤8 mg/mL), OR (vi) the current episode diagnosed or suspected of asthma by the emergency physician? 5. have moderate or severe airway obstruction, defined as a Paediatric Respiratory Asthma Measure (PRAM) score \>3 at baseline, Exclusion Criteria: * Patient will be excluded if : 1. he/she has another chronic respiratory condition (such as bronchopulmonary dysplasia or cystic fibrosis); 2. there is a reasonable suspicion of bronchiolitis or foreign body aspiration; 3. he/she has a prior history of hypersensitivity to salbutamol, ipratropium bromide or oral prednisone/prednisolone; 4. he/she has a relative or absolute contraindication to receiving oral corticosteroids such as recent exposure to varicella or live vaccine in past 14 days, 5. there is confirmed or suspected pregnancy.