Date	Event	Description
3 April 2018	New search has been performed	New authors joined the team to update the review. We updated the searches and included five new trials. Three were newly identified trials (Dobrovoljac 2012; Garbutt 2013; Soleimani 2013); one was previously excluded (Chub‐Uppakarn 2007); and one was previously awaiting classification (Eboriadou 2010). We excluded six new trials, Eghbali 2016; Faghihinia 2007; Faraji‐Goodarzi 2018; Gill 2017; Mohammadzadeh 2014; Roked 2015, and one ongoing trial (NCT01748162). We included one new ongoing trial (ACTRN12609000290291). In this update we assessed the risk of bias and the certainty of the evidence. We added two new primary outcomes: change in croup score after two hours, and patient improvement after two hours. We added adverse events as a secondary outcome and 'Summary of findings' tables. We added two new comparisons: oral compared to nebulised dexamethasone, and dexamethasone compared to beclomethasone.
3 April 2018	New citation required and conclusions have changed	Our conclusions have changed. The previous version of this review concluded that glucocorticoids, as compared to placebo, reduce croup symptoms within six hours and that the effect lasts 12 hours. We conclude that glucocorticoids, as compared to placebo, reduce croup symptoms within two hours and that the effect lasts at least 24 hours.