BMJ Clin Evid. 2014 Sep 29:2014:0321.


Introduction: Croup is characterised by the abrupt onset, most commonly at night, of a barking cough, inspiratory stridor, hoarseness, and respiratory distress due to upper airway obstruction. It leads to signs of upper airway obstruction, and must be differentiated from acute epiglottitis, bacterial tracheitis, or an inhaled foreign body. Croup affects about 3% of children per year, usually between the ages of 6 months and 3 years, and 75% of infections are caused by parainfluenza virus. Symptoms usually resolve within 48 hours, but severe upper airway obstruction can, rarely, lead to respiratory failure and arrest.

Methods and outcomes: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments in children with mild croup and moderate to severe croup? We searched: Medline, Embase, The Cochrane Library, and other important databases up to November 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

Results: We found 19 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

Conclusions: In this systematic review we present information relating to the effectiveness and safety of the following interventions: corticosteroids (dexamethasone, intramuscular and oral), nebulised budesonide, oral prednisolone, heliox, humidification, and nebulised adrenaline (racemate and L-adrenaline [ephinephrine]).

Publication types

  • Review
  • Systematic Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use
  • Budesonide / therapeutic use
  • Cough / drug therapy
  • Cough / etiology*
  • Cough / therapy*
  • Croup / complications*
  • Croup / drug therapy
  • Croup / therapy*
  • Epinephrine / therapeutic use
  • Helium / therapeutic use
  • Humans
  • Humidity
  • Oxygen / therapeutic use
  • Prednisolone / therapeutic use


  • Adrenal Cortex Hormones
  • Helium
  • Budesonide
  • heliox
  • Prednisolone
  • Oxygen
  • Epinephrine