The aim of this study is to compare the efficacy of a single dose of intramuscular dexamethasone versus 3 days of twice-daily oral prednisolone in the management of mild to moderate asthma exacerbations in children and test whether this single dose of intramuscular dexamethasone 0.6 mg/kg (max. 18 mg) is equal to prednisolone 1 mg/kg/day (max. 40 mg) in the treatment of exacerbations of asthma in children, as measured by the Pediatric Respiratory Assessment Measure (PRAM).