Approach

The diagnosis of croup depends upon a careful history and physical examination. The key features are the characteristic sudden-onset, seal-like barky cough, often accompanied by stridor and chest wall (intercostal) or sternal indrawing. Symptoms are typically worse at night and increase with agitation.

There may be a history of prior nonspecific upper respiratory tract symptoms (coryza, non-barky cough, mild fever), although the seal-like barky cough may also present abruptly with no preceding illness. Although not essential to the diagnosis, there is commonly a hoarse voice.

Clinical presentation

Presentations may range from mild symptoms to impending respiratory failure.[19] The physician should look out for the following symptoms and signs according to severity:

  • Mild: seal-like barky cough but no stridor or sternal/intercostal retractions at rest

  • Moderate: seal-like barky cough with stridor and sternal retractions at rest; no agitation or lethargy

  • Severe: seal-like barky cough with stridor and sternal/intercostal retractions, associated with agitation or lethargy

  • Impending respiratory failure: increasing upper airway obstruction, sternal/intercostal retractions, asynchronous chest wall and abdominal movement, fatigue, and signs of hypoxia (pallor or cyanosis) and hypercapnia (decreased level of consciousness secondary to rising PaCO₂). The degree of chest wall retractions may diminish with the onset of respiratory failure as the child tires.

    Stridor
    Stridor

    Auscultation sounds: Stridor

The clinician must consider the differential diagnosis during the physical examination. In particular, if epiglottitis is suspected, examination of the oropharynx or manipulation of the neck is contraindicated as it may precipitate further airway obstruction.

Work-up

Croup is largely a clinical diagnosis.[20]

  • Do not order comprehensive viral panel testing for patients who have a clinical presentation of croup as this is not necessary for diagnosis and the results are not helpful for routine management.[19][20]​​[21]​​​

  • Do not order radiographs for children with typical clinical signs of croup because radiologic assessment is not necessary for diagnosis.[21]​ Croup is often associated with the steeple sign which indicates glottic and subglottic narrowing. However, this finding is neither specific nor sensitive for croup.[20][22]

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