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Croup: Clinical features, evaluation, and diagnosis

Charles R Woods, MD, MS
Section Editors
Gregory Redding, MD
Anna H Messner, MD
Sheldon L Kaplan, MD
Deputy Editor
Carrie Armsby, MD, MPH


Croup is a respiratory illness characterized by inspiratory stridor, cough, and hoarseness. These symptoms result from inflammation in the larynx and subglottic airway. A barking cough is the hallmark of croup among infants and young children, whereas hoarseness predominates in older children and adults. Although croup usually is a mild and self-limited illness, significant upper airway obstruction, respiratory distress, and, rarely, death, can occur.

The clinical features, evaluation, and diagnosis of croup will be discussed here. The management of croup is discussed separately. (See "Croup: Approach to management" and "Croup: Pharmacologic and supportive interventions".)


The term croup has been used to describe a variety of upper respiratory conditions in children, including laryngitis, laryngotracheitis, laryngotracheobronchitis, bacterial tracheitis, or spasmodic croup [1]. These terms are defined below. In the past, the term croup also has been applied to laryngeal diphtheria (diphtheritic or membranous croup), which is discussed separately. (See "Epidemiology and pathophysiology of diphtheria" and "Clinical manifestations, diagnosis, and treatment of diphtheria".)

Throughout this review, the term croup will be used to refer to laryngotracheitis. Laryngotracheobronchitis, laryngotracheobronchopneumonitis, bacterial tracheitis, and spasmodic croup are designated specifically as such.

Laryngitis – Laryngitis refers to inflammation limited to the larynx and manifests itself as hoarseness [2]. It usually occurs in older children and adults and, similar to croup, is frequently caused by a viral infection. The etiology, management, and evaluation of other causes of hoarseness are discussed in detail separately. (See "Common causes of hoarseness in children" and "Hoarseness in children: Evaluation".)

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Literature review current through: Nov 2017. | This topic last updated: May 10, 2016.
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  1. Cherry JD. Clinical practice. Croup. N Engl J Med 2008; 358:384.
  2. Cherry JD. Croup (laryngitis, laryngotracheitis, spasmodic croup, laryngotracheobronchitis, bacterial tracheitis, and laryngotracheobronchopneumonitis) and epiglottitis (supraglottitis). In: Feigin and Cherry’s Textbook of Pediatric Infectious Diseases, 7th ed, Cherry JD, Harrison GJ, Kaplan SL, et al (Eds), Elsevier Saunders, Philadelphia 2014. p.241.
  3. Hodnett BL, Simons JP, Riera KM, et al. Objective endoscopic findings in patients with recurrent croup: 10-year retrospective analysis. Int J Pediatr Otorhinolaryngol 2015; 79:2343.
  4. Cooper T, Kuruvilla G, Persad R, El-Hakim H. Atypical croup: association with airway lesions, atopy, and esophagitis. Otolaryngol Head Neck Surg 2012; 147:209.
  5. Peltola V, Heikkinen T, Ruuskanen O. Clinical courses of croup caused by influenza and parainfluenza viruses. Pediatr Infect Dis J 2002; 21:76.
  6. Counihan ME, Shay DK, Holman RC, et al. Human parainfluenza virus-associated hospitalizations among children less than five years of age in the United States. Pediatr Infect Dis J 2001; 20:646.
  7. Rihkanen H, Rönkkö E, Nieminen T, et al. Respiratory viruses in laryngeal croup of young children. J Pediatr 2008; 152:661.
  8. Weinberg GA, Hall CB, Iwane MK, et al. Parainfluenza virus infection of young children: estimates of the population-based burden of hospitalization. J Pediatr 2009; 154:694.
  9. Frost HM, Robinson CC, Dominguez SR. Epidemiology and clinical presentation of parainfluenza type 4 in children: a 3-year comparative study to parainfluenza types 1-3. J Infect Dis 2014; 209:695.
  10. Kuypers J, Martin ET, Heugel J, et al. Clinical disease in children associated with newly described coronavirus subtypes. Pediatrics 2007; 119:e70.
  11. Sung JY, Lee HJ, Eun BW, et al. Role of human coronavirus NL63 in hospitalized children with croup. Pediatr Infect Dis J 2010; 29:822.
  12. van der Hoek L, Sure K, Ihorst G, et al. Croup is associated with the novel coronavirus NL63. PLoS Med 2005; 2:e240.
  13. Døllner H, Risnes K, Radtke A, Nordbø SA. Outbreak of human metapneumovirus infection in norwegian children. Pediatr Infect Dis J 2004; 23:436.
  14. Bjornson CL, Johnson DW. Croup. Lancet 2008; 371:329.
  15. Segal AO, Crighton EJ, Moineddin R, et al. Croup hospitalizations in Ontario: a 14-year time-series analysis. Pediatrics 2005; 116:51.
  16. Rosychuk RJ, Klassen TP, Metes D, et al. Croup presentations to emergency departments in Alberta, Canada: a large population-based study. Pediatr Pulmonol 2010; 45:83.
  17. Pruikkonen H, Dunder T, Renko M, et al. Risk factors for croup in children with recurrent respiratory infections: a case-control study. Paediatr Perinat Epidemiol 2009; 23:153.
  18. Salzman MB, Filler HF, Schechter CB. Passive smoking and croup. Arch Otolaryngol Head Neck Surg 1987; 113:866.
  19. Lee DR, Lee CH, Won YK, et al. Clinical characteristics of children and adolescents with croup and epiglottitis who visited 146 Emergency Departments in Korea. Korean J Pediatr 2015; 58:380.
  20. Marx A, Török TJ, Holman RC, et al. Pediatric hospitalizations for croup (laryngotracheobronchitis): biennial increases associated with human parainfluenza virus 1 epidemics. J Infect Dis 1997; 176:1423.
  21. DAVISON FW. Acute laryngeal obstruction in children. J Am Med Assoc 1959; 171:1301.
  22. Davison FW. Acute obstructive laryngitis in children. Penn Med J 1950; 53:250.
  23. Szpunar J, Glowacki J, Laskowski A, Miszke A. Fibrinous laryngotracheobronchitis in children. Arch Otolaryngol 1971; 93:173.
  24. MORGAN EA, WISHART DE. Laryngotracheo-bronchitis (a statistical review of 549 cases). Can Med Assoc J 1947; 56:8.
  25. Orton HB, Smith EL, Bell HO, et al. Acute laryngotracheobronchitis: analysis of sixty-two cases with report of autopsies in eight cases. Arch Otolaryngol 1941; 33:926.
  26. Richards L. A further study of the pathology of acute laryngo-tracheobronchitis in children. Ann Otol Rhinol Laryngol 1938; 47:326.
  27. Delany DR, Johnston DR. Role of direct laryngoscopy and bronchoscopy in recurrent croup. Otolaryngol Head Neck Surg 2015; 152:159.
  28. Hide DW, Guyer BM. Recurrent croup. Arch Dis Child 1985; 60:585.
  29. Van Bever HP, Wieringa MH, Weyler JJ, et al. Croup and recurrent croup: their association with asthma and allergy. An epidemiological study on 5-8-year-old children. Eur J Pediatr 1999; 158:253.
  30. Gilger MA. Pediatric otolaryngologic manifestations of gastroesophageal reflux disease. Curr Gastroenterol Rep 2003; 5:247.
  31. Welliver RC, Sun M, Rinaldo D. Defective regulation of immune responses in croup due to parainfluenza virus. Pediatr Res 1985; 19:716.
  32. Welliver RC, Wong DT, Middleton E Jr, et al. Role of parainfluenza virus-specific IgE in pathogenesis of croup and wheezing subsequent to infection. J Pediatr 1982; 101:889.
  33. Thompson M, Vodicka TA, Blair PS, et al. Duration of symptoms of respiratory tract infections in children: systematic review. BMJ 2013; 347:f7027.
  34. Cherry JD. The treatment of croup: continued controversy due to failure of recognition of historic, ecologic, etiologic and clinical perspectives. J Pediatr 1979; 94:352.
  35. Kaditis AG, Wald ER. Viral croup: current diagnosis and treatment. Pediatr Infect Dis J 1998; 17:827.
  36. Duval M, Tarasidis G, Grimmer JF, et al. Role of operative airway evaluation in children with recurrent croup: a retrospective cohort study. Clin Otolaryngol 2015; 40:227.
  37. Rankin I, Wang SM, Waters A, et al. The management of recurrent croup in children. J Laryngol Otol 2013; 127:494.
  38. Jabbour N, Parker NP, Finkelstein M, et al. Incidence of operative endoscopy findings in recurrent croup. Otolaryngol Head Neck Surg 2011; 144:596.
  39. Chun R, Preciado DA, Zalzal GH, Shah RK. Utility of bronchoscopy for recurrent croup. Ann Otol Rhinol Laryngol 2009; 118:495.
  40. Mauro RD, Poole SR, Lockhart CH. Differentiation of epiglottitis from laryngotracheitis in the child with stridor. Am J Dis Child 1988; 142:679.
  41. Kasian GF, Bingham WT, Steinberg J, et al. Bacterial tracheitis in children. CMAJ 1989; 140:46.
  42. Tibballs J, Watson T. Symptoms and signs differentiating croup and epiglottitis. J Paediatr Child Health 2011; 47:77.
  43. Alberta Clinical Practice Guidelines Guideline Working Group. Guidelines for the diagnosis and management of croup. www.topalbertadoctors.org/download/252/croup_guideline.pdf (Accessed on March 13, 2015).
  44. Diaz JH, Lockhart CH. Early diagnosis and airway management of acute epiglottitis in children. South Med J 1982; 75:399.
  45. Westley CR, Cotton EK, Brooks JG. Nebulized racemic epinephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child 1978; 132:484.
  46. Clarke M, Allaire J. An evidence-based approach to the evaluation and treatment of croup in children. Pediatric Emergency Medicine Practice 2012; 9:1.
  47. Mills JL, Spackman TJ, Borns P, et al. The usefulness of lateral neck roentgenograms in laryngotracheobronchitis. Am J Dis Child 1979; 133:1140.
  48. Bernstein T, Brilli R, Jacobs B. Is bacterial tracheitis changing? A 14-month experience in a pediatric intensive care unit. Clin Infect Dis 1998; 27:458.
  49. Cherry JD. Newer respiratory viruses: their role in respiratory illnesses of children. In: Advances in Pediatrics, Vol 20, Schulman I (Ed), Mosby Year Book, Chicago 1973. p.225.
  50. Denny FW, Clyde WA Jr. Acute lower respiratory tract infections in nonhospitalized children. J Pediatr 1986; 108:635.
  51. Henrickson KJ, Hoover S, Kehl KS, Hua W. National disease burden of respiratory viruses detected in children by polymerase chain reaction. Pediatr Infect Dis J 2004; 23:S11.
  52. Gohil R, Culshaw J, Jackson P, Singh S. Accidental button battery ingestion presenting as croup. J Laryngol Otol 2014; 128:292.
  53. Lin CY, Chi H, Shih SL, et al. A 4-year-old boy presenting with recurrent croup. Eur J Pediatr 2010; 169:249.
  54. Hsia SH, Lin JJ, Wu CT, et al. Guillain-Barré syndrome presenting as mimicking croup. Am J Emerg Med 2010; 28:749.e1.