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What causes stridor? 14 possible conditions

What Is Stridor?

Stridor is a high-pitched, wheezing sound caused by disrupted airflow. Airflow is usually disrupted by a blockage in the larynx (voice box) or trachea (windpipe). It is most noticeable when breathing in (inspiration/inhaling), though it can sometimes be heard when breathing out (expiration/exhaling). Stridor affects children more often than adults.

In infants, a condition called laryngomalacia is usually the cause of stridor. It may be quieter when your child is lying on his or her stomach, and louder when lying on his or her back.

Larynogomalacia is most noticeable when your child is about six months old. It may start as soon as a few days after birth. As your child ages, his or her airway stiffens, and the stridor often goes away. Stridor may go away by the time your child is two years old. For some children, it may continue for another year or two.

Stridor may also be called “abnormal breathing sounds,” “musical breathing,” or “extrathoracic airway obstruction.”

Who Is at Risk for Stridor?

Children have narrower, softer airways than adults do. They are much more likely to develop stridor. The condition should be treated immediately to prevent further blockage. If the airway is completely blocked, the child will not be able to breathe.

What Causes Stridor?

According to the University of Missouri (UM), laryngomalacia is responsible for 50 to 75 percent of stridor cases in infants. Laryngomalacia is caused by soft structures and tissues that get in the way of the airway (UM). It often goes away as your child ages and his or her airways harden.

Symptoms of laryngomalacia include:

  • a low-pitched or squeaky breathing sound. This sound may be more noticeable when the child is lying on his or her back, feeding, or crying.
  • a hoarse cry
  • poor weight gain
  • trouble nursing
  • general difficulty breathing

Laryngomalacia is sometimes present along with gastric reflux (stomach acid coming up into the throat).

Stridor may also be caused by:

  • an object blocking the airway
  • swelling in your child’s 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 (viral respiratory infection)

  • bronchitis (inflammation of the airways leading to the lungs)
  • tonsillitis (inflammation of the lymph nodes at the back of the mouth and top of the throat by viruses or bacteria)
  • epiglottitis (inflammation the tissue covering the windpipe caused by the H. influenza bacterium)
  • tumors (less common) or abscesses (a collection of pus or fluid)

vocal cord paralysis

Other conditions that may cause stridor include:

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

How Is Stridor Diagnosed?

Your doctor will try to find the cause of your child’s stridor. He or she will give your child a physical examination and ask questions about your child’s 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 child’s face or skin
  • if your child has been ill recently
  • if your child could have put a foreign object into his or her mouth
  • if your child is struggling to breathe

Your doctor may order tests, such as:

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

If your doctor suspects an infection, he or she will order a sputum culture. This test checks material your child coughs up from his or her lungs for viruses and bacteria. It helps the doctor see if an infection, such as croup, is present.

How Is Stridor Treated?

Do not wait to see if stridor goes away without medical treatment. Visit your doctor and follow his or her advice. Treatment options vary depending on the age and health of 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 and/or surgery in severe cases
  • require additional monitoring

Emergency Care

Contact your doctor immediately if you see:

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

Article Sources:

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See a list of possible causes in order from the most common to the least.


Choking Adult Or Child Over 1 Year

This condition is considered a medical emergency. Urgent care may be required.

Choking occurs when an object, food, or liquid becomes lodged in the throat. Emergency signs of choking include the inability to speak, cough, or breathe. Lips may start to turn blue from lack of oxygen.

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Diphtheria is a sometimes fatal bacterial infection that affects the nose and throat's membranes. Diptheria of the skin may show up as a red rash.

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This condition is considered a medical emergency. Urgent care may be required.

When people with severe allergies are exposed to their allergen, a life-threatening reaction called anaphylaxis can result: a series of symptoms such as rash, abdominal pain, and difficulty breathing and shock.

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This condition is considered a medical emergency. Urgent care may be required.

Epiglottitis is characterized by inflamed tissue in your epiglottis. It's a potentially life-threatening illness. The epiglottis is at the base of the tongue.

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Lung Cancer Overview

Lung cancer is a cancer that originates in the lungs. Lung cancer often goes undetected in the early stages, since symptoms don't usually present themselves until the advanced stages of the disease.

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Angioedema (Giant Hives)

Angioedema is severe swelling of the skin. The face is one area prone to swelling from this condition.

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Tonsillitis occurs when the tonsils (the lymph tissue in your throat) become infected. Symptoms include sore throat, fever, and swollen tonsils. Fortunately, it's normally easily diagnosed and treated.

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Laryngitis occurs when your voice box and vocal cords become swollen and irritated. This fairly common condition often causes hoarseness or loss of voice.

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Deviated Septum

The nasal septum is a thin structure, separating the two sides of the nose. If it is not in the middle of the nose, then it is deviated.

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Croup is a viral condition that causes swelling around the vocal cords. It is characterized by breathing difficulties and a bad cough that sounds like a barking seal. Many of the viruses responsible for croup also caus...

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Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common kind of lung cancer, comprising 85 to 90 percent of lung cancer diagnoses. It does not grow as quickly as the other type of lung cancer, small cell lung cancer.

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Chemical Burns

This condition is considered a medical emergency. Urgent care may be required.

Chemical burns occur when the skin or eyes come into contact with irritants, such as acids or bases. Symptoms vary, but skin reactions, pain or numbness are common.

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Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. Swelling of the face is one potential sign of lung cancer.

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Transfusion Reactions

A transfusion reaction is a rare condition that occurs when a person receives a transfusion with blood that is not matched to their blood type. This may cause symptoms such as back pain, fever, fainting, or dizziness.

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.