The aim of the prospective cohort study is to: (1) document the magnitude of response to oral corticosteroids administered to children presenting to the emergency department with moderate or severe asthma and (2) quantify clinically available potential determinants of the response to corticosteroids, such as age, gender, triggers of the index exacerbation, environmental tobacco smoke (ETS), gene polymorphisms, and their interactions.

The objective of the large multicentre cohort study is to quantify the response to oral corticosteroids in children aged 1 to 17 years presenting to the ED with a moderate or severe asthma exacerbation.

The main outcome is hospital admission within 72 hours of the oral corticosteroid administration.

Secondary outcomes include the change in Pediatric Respiratory Assessment Measure (PRAM), length of active treatment and other markers of response to therapy in the ED as well as markers of recovery over the next 10 days.

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.

Children aged 1 to 17 years with moderate to severe asthma with Pediatric Respiratory Assessment Measure (PRAM) ≥4.