Cruz 1995.

Methods	Randomised double‐blind controlled trial
Participants	Study period: November 1992 to December 1993 Setting: emergency department at the Children's Hospital of Michigan, USA Inclusion criteria: children aged 6 months to 5 years reporting to the emergency department with a clinical diagnosis of acute laryngotracheitis or viral croup. Westley croup score of at least 2 and able to be managed as outpatients Exclusion criteria: history of prior intubation; structural airway anomalies; those requiring more than 1 racemic epinephrine treatment; hospitalisation; β‐agonist therapy; received steroids in the past 24 hours Baseline demographics (N = 45): proportion male: treatment: 74%; control: 63% median (SD) age in months: treatment: 18.0 (19.0); control: 21.0 (8.0) median (range) Westley croup score: treatment: 3 (2 to 5); control: 3 (2 to 5)
Interventions	Treatment (N = 19): single 0.60 mg/kg (maximum 10 mg) dose of intramuscular dexamethasone Control (N = 19): equal volume of placebo (normal saline)
Outcomes	Return visits to the emergency department; patient improvement 24 hours after discharge
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: insufficient information provided to judge.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information provided to judge.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "double blind" "Both the patients and the investigators were blinded to the content of the syringe" "the drug code was broken only after the last patient had completed the study"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: no description of a third‐party outcome assessor. Carried over judgement from blinding of participants and personnel
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: 16% (N = 7) were excluded or lost to follow‐up, unclear if losses were balanced between groups.
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol identified. All prespecified outcomes from methods appear in results.
Other bias	Low risk	Comment: no other sources of bias identified.
Overall risk of bias All outcomes	Unclear risk	Comment: at least 1 domain judged as unclear risk, and no domains judged as high risk.