Causes
By Mayo Clinic staffCroup is often caused by the parainfluenza virus. Less often, respiratory syncytial virus or various other respiratory viruses cause croup.
Your child may contract a virus by breathing infected respiratory droplets coughed or sneezed into the air. Virus particles in these droplets may also survive on toys and other surfaces. If your child touches a contaminated surface and then touches his or her eyes, nose or mouth, an infection may follow.
Rarely, croup may be caused by a bacterial infection.
- Fort GG. Laryngotracheobronchitis. In: Ferri FF. Ferri's Clinical Advisor 2010. St. Louis, Mo.: Mosby; 2009. http://www.mdconsult.com/das/book/body/204796489-3/0/2088/366.html#4-u1.0-B978-0-323-05609-0..00021-6--sc0030_7544. Accessed June 8, 2010.
- Roosevelt GE. Acute inflammatory upper airway obstruction (croup, epiglottitis, laryngitis, and bacterial tracheitis). In: Kliegman RM, et al. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/das/book/body/204796489-4/1010564370/1608/906.html#4-u1.0-B978-1-4160-2450-7..50384-4--cesec10_7443. Accessed June 8, 2010.
- Everard ML. Acute bronchiolitis and croup. Pediatric Clinics of North America. 2009;56:119.
- Woods CR. Clinical features, evaluation, and diagnosis of croup. http://www.uptodate.com/home/index.html. Accessed June 8, 2010.
- Woods CR. Approach to the management of croup. http://www.uptodate.com/home/index.html. Accessed June 8, 2010.
- Human parainfluenza viruses (common cold and croup). Centers for Disease Control and Prevention. http://www.cdc.gov/ncidod/dvrd/revb/respiratory/hpivfeat.htm. Accessed July 1, 2010.
- Hoecker JL (expert opinion). Mayo Clinic, Rochester, Minn. June 29, 2010.

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