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Stridor is a high-pitched, wheezing sound caused by disrupted airflow. Stridor may also be called musical breathing or extrathoracic airway obstruction.

Airflow is usually disrupted by a blockage in the larynx (voice box) or trachea (windpipe). Stridor affects children more often than adults.

Types of stridor

There are three types of stridor. Each type can give your doctor a clue about what is causing it.

Inspiratory stridor

In this type, you can only hear the abnormal sound when you breathe in. This indicates an issue with the tissue above the vocal cords.

Expiratory stridor

People with this type of stridor only experience abnormal sounds when they breathe out. Blockage in the windpipe causes this type.

Biphasic stridor

This type causes the abnormal sound when a person breathes in and out. When the cartilage near the vocal cords narrows it causes these sounds.

What causes stridor?

Stridor may be caused by:

  • an object blocking the airway
  • swelling in your throat or upper airway
  • trauma to the airway, such as a fracture in the neck or an object stuck in the nose or throat
  • neck surgery
  • inhaling smoke
  • swallowing a harmful substance that causes damage to the airway
  • croup, a viral respiratory infection
  • vocal cord paralysis
  • bronchitis, an inflammation of the airways leading to the lungs
  • tonsillitis, an inflammation of the lymph nodes at the back of the mouth and top of the throat by viruses or bacteria
  • epiglottitis, an inflammation of the tissue covering the windpipe caused by the H. influenza bacterium
  • tumors
  • abscesses, a collection of pus or fluid
  • laryngomalacia

In infants, a condition called laryngomalacia is usually the cause of stridor. Soft structures and tissues that obstruct the airway cause laryngomalacia. It often goes away as your child ages and their airways harden. It may be quieter when your child is lying on their stomach, and louder when lying on their back. Laryngomalacia is most noticeable when your child is about 6 months old. It may start as soon as a few days after birth. Stridor usually goes away by the time your child is 2 years old.

Other conditions that may cause stridor include:

  • Subglottic stenosis is when the voice box is too narrow. Many children outgrow this condition, though surgery may be necessary in severe cases.
  • Subglottic hemangioma is when a mass of blood vessels forms and obstructs the airway. This condition is rare and may need surgery.
  • Vascular rings occur when an outer artery or vein compressed the windpipe. Surgery may release the compression.

Who is at risk for stridor?

Children have narrower, softer airways than adults do. They’re much more likely to develop stridor. To prevent further blockage, treat the condition immediately. If the airway is completely blocked, your child won’t be able to breathe.

How is stridor diagnosed?

Your doctor will try to find the cause of you or your child’s stridor. They’ll give you or your child a physical examination and ask questions about medical history.

Your doctor may ask questions about:

  • the sound of the abnormal breathing
  • when you first noticed the condition
  • other symptoms, such as a blue color in your face or your child’s face or skin
  • if you or your child has been ill recently
  • if your child could have put a foreign object in their mouth
  • if you or your child is struggling to breathe

Your doctor may also order tests, such as:

  • X-rays to check you or your child’s chest and neck for signs of blockage
  • CT scan of the chest
  • bronchoscopy to provide a clearer view of the airway
  • laryngoscopy to examine the voice box
  • pulse oximetry and arterial blood gases test to measure the amount of oxygen in the blood

If your doctor suspects an infection, they’ll order a sputum culture. This test checks material you or your child cough up from the lungs for viruses and bacteria. It helps your doctor see if an infection, such as croup, is present.

How is stridor treated?

Don’t wait to see if stridor goes away without medical treatment. Visit your doctor and follow their advice. Treatment options depend on the age and health of you or your child, as well as the cause and severity of the stridor.

Your doctor may:

  • refer you to an ear, nose, and throat specialist
  • provide oral or injected medication to decrease swelling in the airway
  • recommend hospitalization or surgery in severe cases
  • require more monitoring

When is emergency care necessary?

Contact your doctor immediately if you see:

  • a blue color in you or your child’s lips, face, or body
  • signs of difficulty breathing, such as the chest collapsing inward
  • weight loss
  • trouble eating or feeding

Content licensed from:

Written by: Natalie Phillips
Medically reviewed on: Apr 14, 2017: University of Illinois-Chicago, School of Medicine

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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