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Stridor (Noisy Breathing)

What Is Stridor (Noisy Breathing)?

Stridor is a high-pitched sound heard best when your child is breathing in (inhaling). It can also be heard when your child is breathing out (exhaling).

Noisy breathing, or stridor, is most often a symptom of a throat or airway problem.

Causes of Stridor

There are many causes of stridor. Anything that causes the airway to be narrowed or partially blocked can cause stridor. Because of their smaller airways, stridor is more common in children than adults. The noisy sound is heard as air passes by the blocked or narrowed part of the voice box (larynx) or the windpipe (trachea).

When an infant is born with stridor, it is called a congenital disorder. This can be caused by:

  • Laryngomalacia: Parts of the voice box are floppy and collapse as a child breathes in. This partially blocks air movement. This is the most common congenital cause of stridor in children. Most children with laryngomalacia grow out of it by 18 months of age.
  • Vocal cord paralysis: There are two vocal cords above the windpipe that are used to make sound. Paralysis means one or both do not move.
  • Subglottic stenosis: This is a narrowing of the airway just below the vocal cords.
  • Subglottic hemangioma: This is a mass formed from abnormal blood vessels that can grow in the airway. It is a very rare condition.

When a child develops stridor later in life, it is called an acquired disorder. This can be the result of infection or trauma.


  • Croup: This is an infection caused by a virus that results in swelling of the airways.
  • Epiglottitis: This is a severe life-threatening infection of the epiglottis (the small lid that closes over windpipe when swallowing). It is caused by bacteria. The swelling of the epiglottis can worsen over time and make it hard or impossible to move air into the lungs. Epiglottitis is rare because infants have routine vaccination for the bacteria that commonly causes the infection (Haemophilus influenza).
  • Tonsillitis: This is an infection of the tonsils (soft tissue in the back of mouth) that can cause the tonsils to get big and swollen. In severe cases it can cause noisy breathing.


  • Foreign body: A foreign body is an object that is swallowed or inhaled. This can cause a blockage of the airway. This may result in stridor and trouble breathing. If the object is in the airway, this is an emergency.
  • Swallowing a harmful material may cause injury to the airway or the esophagus (swallowing tube).
  • Injury to the neck.

Allergic Reaction

Severe allergic reactions may cause swelling in the airway. A rash (hives) and swelling of the lips, tongue, or face may be signs of an allergic reaction.

Diagnosis of Stridor

Stridor is diagnosed from a medical history and a physical examination.

Questions that may be asked:

  • When did the noise start? Did it start all of a sudden?
  • Does anything make it worse or better?
  • Are there any eating and drinking problems?
  • Could the child have put anything in their mouth? or choked on anything?
  • Has the child had any recent illnesses?
  • Does the child have any allergies?

Physical examination:

Look at:

  • Nose: nasal flaring (Nostrils get wider when breathing)
  • Mouth: for throat swelling
  • Neck: for birth marks or retractions (neck pulling in)
  • Chest: retractions (ribs pulling in)

Listen to:

  • The sound your child makes
  • When it happens (breathing in, breathing out, or both)

Your healthcare provider may order one or more of these tests to help find out what is causing this.

  • Flexible nasopharyngoscopy: Passing a tiny, soft tube with a camera and light at the end through the nose and into the airway.
  • X-ray of chest or neck: To look for swelling, narrowing or objects in the airway
  • Bronchoscopy: A flexible or rigid bronchoscope (tube with light on end). This is done under anesthesia in the operating room.

Treatment of Stridor

Treatment for stridor depends on the cause and how severe the condition is. Other experts may be needed to create a treatment plan unique to your child, such as speech pathologists, gastroenterologists (GI doctor), pulmonologists (lung doctor), social workers and nurses.

Treatment may include:

  • Observation: Watch the child to see if the condition gets better with time
  • Medicine: Reflux medicine, steroids, or antibiotics
  • Surgery: To remove or repair airway blockages

Call Your Health Care Provider If …

  • Your newborn has noisy breathing.
  • Your child has inhaled or swallowed an object into their airway.
  • Call 911 right away if your child has any signs of breathing problems:
    • Skin, lips, or fingernails are turning blue.
    • Chest or neck is pulling in.
    • Your child has passed out.
    • Your child has stopped breathing.

Last Updated 10/2021

Reviewed By Daniel von Allmen, MD
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