What is the definition of Stridor?

Stridor is an abnormal, high-pitched, musical breathing sound. It is caused by a blockage in the throat or voice box (larynx). It is most often heard when taking in a breath.

What are the alternative names for Stridor?

Breathing sounds - abnormal; Extrathoracic airway obstruction; Wheezing - stridor


Children are at higher risk of airway blockage because they have narrower airways than adults. In young children, stridor is a sign of airway blockage. It must be treated right away to prevent the airway from becoming completely closed.

The airway can be blocked by an object, swollen tissues of the throat or upper airway, or a spasm of the airway muscles or the vocal cords.

What are the causes for Stridor?

Common causes of stridor include:

  • Airway injury
  • Allergic reaction
  • Problem breathing and a barking cough (croup)
  • Diagnostic tests such as bronchoscopy or laryngoscopy
  • Epiglottitis, inflammation of the cartilage that covers the windpipe
  • Inhaling an object such as a peanut or marble (foreign body aspiration)
  • Swelling and irritation of the voice box (laryngitis)
  • Neck surgery
  • Use of a breathing tube for a long time
  • Secretions such as phlegm (sputum)
  • Smoke inhalation or other inhalation injury
  • Swelling of the neck or face
  • Swollen tonsils or adenoids (such as with tonsillitis)
  • Vocal cord cancer


Follow your health care provider's advice to treat the cause of the problem.

When should I contact a medical professional for Stridor?

Stridor may be a sign of an emergency. Call your provider right away if there is unexplained stridor, especially in a child.


In an emergency, the provider will check the person's temperature, pulse, breathing rate, and blood pressure, and may need to do abdominal thrusts.

A breathing tube may be needed if the person can't breathe properly.

After the person is stable, the provider may ask about the person's medical history, and perform a physical exam. This includes listening to the lungs.

Parents or caregivers may be asked the following medical history questions:

  • Is the abnormal breathing a high-pitched sound?
  • Did the breathing problem start suddenly?
  • Could the child have put something in their mouth?
  • Has the child been ill recently?
  • Is the child's neck or face swollen?
  • Has the child been coughing or complaining of a sore throat?
  • What other symptoms does the child have? (For example, nasal flaring or a bluish color to the skin, lips, or nails)
  • Is the child using chest muscles to breathe (intercostal retractions)?

Tests that may be done include:

  • Arterial blood gas analysis
  • Bronchoscopy
  • Chest CT scan
  • Laryngoscopy (examination of the voice box)
  • Pulse oximetry to measure blood oxygen level
  • X-ray of the chest or neck


Griffiths AG. Chronic or recurrent respiratory symptoms. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 401.

Rose E. Pediatric respiratory emergencies: upper airway obstruction and infections. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 167.

  • Condition: Pulmonary Infection Secondary to Intracerebral Hemorrhage (ICH)
  • Journal: Medicine
  • Treatment Used: Tanreqing Injection (TRQI) Combined with Antibiotics vs. Antibiotics Alone
  • Number of Patients: 1122
  • Published —
This review of the literature investigated the effectiveness of Tanreqing injection (TRQI) for the treatment of lung infection secondary to intracerebral hemorrhage (ICH).
  • Condition: Adult Pneumonia
  • Journal: Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica
  • Treatment Used: Lianhua Qingwen Adjuvant Treatment
  • Number of Patients: 2007
  • Published —
This review of the literature evaluated the safety and effectiveness of Lianhua Qingwen in the treatment of adult pneumonia.
Clinical Trial
  • Status: Not yet recruiting
  • Phase: Phase 4
  • Intervention Type: Drug
  • Participants: 300
  • Start Date: September 2021
Bronchodilators for Wheeze in Young Children Presenting to Primary Care: a Randomised, Placebo-controlled, Multicentre, Parallel Group Trial
Clinical Trial
  • Status: Not yet recruiting
  • Phase: Phase 3
  • Intervention Type: Drug
  • Participants: 1476
  • Start Date: May 2021
AZithromycin Therapy in Preschoolers With a Severe Wheezing Episode Diagnosed at the Emergency Department (AZ-SWED)