International guidelines have recommended the use of inhaled beta-2 agonists and systemic corticosteroids (SC) as the first-line treatment for acute asthma. Objective: To evaluate the evidence for the efficacy of inhaled corticosteroids (ICS) in addition to SC compared to SC alone in children with acute asthma in the ED or during hospitalization. Data sources: Five electronic databases were searched. Study Selection: All RCTs that compared ICS (via nebulizer or metered dose inhaler) plus SC (oral or parenteral) with placebo (or standard care) plus SC were included without language restriction. Data extraction: Two reviewers independently reviewed all studies. The primary outcomes were hospital admission or hospital length of stay [LOS], and secondary outcomes were readmissions during follow-up, ED-LOS, lung function, asthma clinical score, oxygen saturation, and heart and respiratory rates. Results: Nine studies (n=1473) met the inclusion criteria. In all the studies, the ICS was budesonide. Compared to SC alone, adding budesonide to SC did not affect hospitalization rate, but decreased hospital LOS by more than one day (MD= -29.08 hours [-39.9 to -18.3]; I2=0%, p=<0.00001). Moreover, adding budesonide (especially with ≥2mg doses) significantly improved the acute asthma severity score among patients at ED. Conclusions: Compared to SC alone, adding budesonide to SC did not affect hospitalization rate, but decreases the LOS and improves the acute asthma score in children at ED setting.