Stephen J. Schueler, M.D.

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Croup Underlying Cause


  • The most common cause of croup is respiratory syncytial virus (RSV), but influenza and cold viruses may also cause croup.
  • The infection causes irritation to the lining of the trachea, or windpipe. In response to the irritation, the lining of the trachea swells and produces mucus. This results in narrowing of the airway. Air whistles as it passes through the narrowed airway, which results in a barking cough and noisy breathing.
  • Croup occurs in children, because a child's airway is much narrower than an adult's airway.

Continue to Croup Transmission

Last Updated: Sep 25, 2007 References
Authors: Stephen J. Schueler, MD; John H. Beckett, MD; D. Scott Gettings, MD
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PubMed Croup References
  1. Bjornson CL, Klassen TP, Williamson J, Brant R, Mitton C, Plint A, Bulloch B, Evered L, Johnson DW; Pediatric Emergency Research Canada Network. A randomized trial of a single dose of oral dexamethasone for mild croup. N Engl J Med. 2004 Sep 23;351(13):1306-13. [15385657]
  2. Custer JR. A randomized trial of a single dose of oral dexamethasone for mild croup. J Pediatr. 2005 Mar;146(3):434-5. [15756240]
  3. Griffin S, Ellis S, Fitzgerald-Barron A, Rose J, Egger M. Nebulised steroid in the treatment of croup: a systematic review of randomised controlled trials. Br J Gen Pract. 2000 Feb;50(451):135-41. [10750214]
  4. Johnson D. Croup. Clin Evid. 2004 Dec;(12):401-26. [15865647]
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