Stridor (Noisy Breathing)

What is stridor?

Stridor is noisy breathing that occurs due to obstructed air flow through a narrowed airway. Stridor breathing is not in and of itself a diagnosis, but rather is a symptom or sign that points to a specific airway disorder.

The timing and the sound of your child's noisy breathing provides clues to the type of airway disorder:

  • Inspiratory stridor occurs when your child breathes in and it indicates a collapse of tissue above the vocal cords. 
  • Expiratory stridor occurs when your child breathes out and it indicates a problem further down the windpipe. 
  • Biphasic stridor occurs when your child breathes in and out, and it indicates a narrowing of the subglottis, the cartilage right below the vocal cords.


Any process that causes airway narrowing can cause stridor. With infants, stridor usually indicates a congenital disorder (problem that your child is born with), including laryngomalacia, vocal cord paralysis or subglottic stenosis. If your toddler or older child develops stridor, it may occur as a result of an infection such as croup or papillomatosis. In rare circumstances, stridor can occur secondary to trauma or foreign body aspiration.

Testing and diagnosis

The evaluation of stridor begins with a history and physical examination of your child. Important history will include questions regarding the onset, duration and progression of stridor as well as associated feeding or voice disturbances.

The doctor's physical examination begins with an assessment for signs of respiratory distress (nasal flaring, retractions, color change, etc.).

Once the child is determined to be stable, the physician will evaluate specific features of the stridor (inspiratory, expiratory, biphasic) and voice.

The airway doctor may recommend one or more of these diagnostic tests:

  • Flexible laryngoscopy  A test in which the doctor passes a tiny tube with a camera and light at the end through the nose and into the airway to look for problems. 
  • Plain X-ray, airway fluoroscopy, barium swallow, and CT scan of the chest — Films that can help the doctor further evaluate the noisy breathing. 
  • Magnetic resonance imaging or magnetic resonance angiography  An imaging test that shows soft tissues in great detail. MRI/MRA is rarely requested but it is helpful in diagnosing the presence of a vascular ring. A vascular ring is a rare birth defect in which a large blood vessel in the heart — the aortic arch — encircles and squeezes the trachea and esophagus.


Stridor treatment depends upon many factors, such as the cause of the noisy breathing and the severity of the condition. Your child's treatment will be tailored to meet her unique needs. Multidisciplinary care is often provided by a team of airway surgeons, speech pathologists, gastroenterologists, pulmonary physicians, social workers and nurses.

Treatment options may include:

  • Observation  Indicated for patients who have minor degrees of obstruction such as laryngomalacia or mild subglottic stenosis.
  • Medications — Reflux medication and/or steroids to reduce airway swelling.
  • Endoscopic surgery — To remove airway obstructions (i.e. foreign body or cyst) or expand the airway (i.e. for subglottic stenosis) through the windpipe. In many cases, it is performed through a scope.
  • Open surgery — To repair obstructions and scarring through an outside incision.  


Berg E., Naseri I. Sobol S. The role of airway fluoroscopy in the evaluation of children with stridor. Arch Otolaryngol Head Neck Surg. 2003 Mar;129(3):305-9.