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.”
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.
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.
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.
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
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