Chapter 4.6 Conditions presenting with stridor

Presenting sign is stridor

Stridor is a harsh noise during inspiration, which is due to narrowing of the air passages in the oropharynx, subglottis or trachea. If the obstruction is below the larynx, stridor may also occur during expiration.

The major causes of severe stridor are viral croup (commonly caused by measles or other viruses), foreign body inhalation, retropharyngeal abscess, diphtheria and trauma to the larynx (Table 9). It may also occur in early infancy due to congenital abnormalities.


  • first episode or recurrent episode of stridor
  • history of choking
  • stridor present soon after birth