Study	Reason for exclusion
Barnett 1997	Emergency department study Comparing 2 different types of steroids (no placebo)
Becker 1999	Comparing 2 different types of steroids (no placebo)
Chavez 1992	Not RCT Included patients < 12 months
Daugbjerg 1993	Included patients <12 months
Devidayal 1999	Emergency department study
Gonzalez 1994	Included patients < 12 months
Langton‐Hewer 1998	Comparing 3 different types of steroids (no placebo)
Lin 1991	Not RCT Included patients < 12 months
Loren 1980	not located in hospital (residential school)
Pierson 1974	At the onset of this trial randomisation and blinding were carried out adequately. However, at 3 hours into the trial 7 of the control group (almost half) were reassigned to the steroid group because of changes in arterial gasses. These were not reported as withdrawals and were treated as randomised units
Sano 2000	Included patients < 12 months Not RCT

DBRCT = double‐blind, randomized controlled trial; RCT = randomized controlled trial.