The purpose of this study was to determine whether a single intramuscular injection of dexamethasone decreased the duration of symptoms of acute bronchiolitis in young children.

Acute bronchiolitis is an infection of the lower respiratory tract causing inflammation of the small airways, leading to bronchiolar obstruction. Corticosteroids are frequently prescribed as anti-inflammatory drugs. The usefulness of corticosteroids for this disease remains controversial, despite many randomized controlled trials (RCTs). Recently, a meta-analysis and systemic review showed significant improvement in clinical symptoms, length of hospital stay and duration of symptoms in children with this disease after treatment with various regimens of systemic corticosteroids.

Dexamethasone is a long acting corticosteroid with biologic half-life ranging from 36-72 hours. A single dose of dexamethasone has been the standard recommendation for the treatment of croup which has a similar pathophysiology without evidence of adverse effects. Furthermore, there is no previous report of this single dosage form of dexamethasone for the treatment of acute bronchiolitis in young children.

Inclusion Criteria:

• Aged 4 weeks - 24 months
• Has the first episode of wheezing within 7 days
• Has evidence of viral infection
• Requires hospital admission; criteria for admission include one of the following: age < 3 months; respiratory rate > 60 breaths/minute for age < 12 months or 50 breaths/minute for > or equal to 12 months; oxygen saturation in room air < 95% and apathy or refuses feeding.

Exclusion Criteria:

• Initial admission to intensive care unit
• Initial requirement for endotracheal intubation or mechanical ventilation
• A previous history of intubation
• A known history of asthma or response to the first dose of beta2 agonist nebulization
• A history of prematurity
• A history of bronchopulmonary dysplasia or chronic lung disease
• Underlying congenital heart disease or immunodeficiency
• Receives treatment of any form of corticosteroids within 2 weeks
• Has contraindication to corticosteroid treatment