A high-pitched sound when a baby breathes in can be alarming. This noise signals turbulent airflow through a narrowed airway, which is easily obstructed in infants. Understanding the source is the first step toward determining if the issue is minor congestion or a serious condition requiring medical help. The timing of the sound—inhalation or exhalation—is a valuable clue in pinpointing the obstruction’s location.
Clarifying the Sound: Wheezing Versus Stridor
The term “wheezing” is commonly used for noisy breathing, but medically it refers to a high-pitched, whistling sound typically occurring during exhalation. This expiratory sound originates in the lower airways, specifically the bronchi and bronchioles within the lungs, and signifies obstruction or narrowing there. Common causes of true wheezing include conditions like bronchiolitis or asthma.
The sound parents describe as “wheezing when breathing in” is accurately known as stridor. Stridor is a harsh, often high-pitched sound that is loudest during inhalation. This inspiratory timing indicates a partial obstruction or narrowing in the upper airway, which includes the larynx (voice box) and trachea (windpipe). The turbulent airflow in this region produces the characteristic noise as the airway walls collapse slightly during the inspiratory effort.
Common Causes of Inspiratory Sounds in Infants
Laryngomalacia
The most frequent cause of chronic inspiratory stridor is Laryngomalacia, where the laryngeal tissue above the vocal cords is unusually soft. During inhalation, this floppy tissue collapses into the airway, generating the high-pitched sound. Laryngomalacia is usually present from birth and often becomes noticeable within the first few weeks of life. It is generally benign, resolving on its own by 12 to 24 months as the cartilage strengthens.
Croup
Acute inspiratory stridor is often caused by Croup (laryngotracheitis), typically a viral infection affecting the larynx and trachea. This infection causes swelling in the subglottic area below the vocal cords, narrowing the airway. Croup is generally accompanied by a distinctive, barking, seal-like cough and often worsens at night.
Other Causes
A less common cause is Congenital Subglottic Stenosis, a fixed narrowing of the airway below the vocal cords. This narrowing is present from birth due to incomplete formation of the cricoid cartilage ring. Milder cases may only become noticeable when the infant develops a respiratory infection causing minor additional swelling. A sudden, unexplained onset of stridor, especially in a toddler, also raises concern for foreign body aspiration, where an object becomes lodged in the upper airway.
Immediate Action and Emergency Warning Signs
A narrowed airway can quickly become a medical emergency, even if the cause of stridor is temporary. Parents must monitor for signs of increased breathing difficulty. Seek immediate medical attention by calling emergency services or going to the nearest emergency room if severe warning signs appear.
Seek immediate medical attention if you observe:
- Cyanosis (bluish or pale coloring around the lips, nose, or fingertips), indicating critically low oxygen levels.
- Severe retractions, where the skin visibly pulls in between the ribs, above the collarbone, or below the breastbone with each breath.
- Nasal flaring, where the nostrils widen during inhalation.
- Exhaustion, lethargy, or agitation preventing the baby from feeding or drinking.
- The sound is accompanied by drooling, a high fever, or starts suddenly following a choking or gagging episode.
Medical Diagnosis and Treatment
Diagnosis
The first step in managing stridor is a rapid assessment of the baby’s oxygenation and work of breathing. Healthcare providers use pulse oximetry, a non-invasive test using a sensor, to measure blood oxygen saturation levels. A physical examination involves listening to the chest and upper airway to characterize the sound and determine its location.
Diagnostic testing may include an X-ray of the neck and chest to identify foreign objects or assess airway structure. For persistent or concerning stridor, a specialist may perform a flexible laryngoscopy. This involves inserting a thin, lighted tube through the nose to visualize the larynx and vocal cords. This procedure helps confirm diagnoses like Laryngomalacia or Vocal Cord Paralysis.
Treatment
Treatment is determined by the underlying cause and severity of the airway narrowing. Mild Laryngomalacia is typically managed with observation, often including treatment for associated conditions like gastroesophageal reflux. Acute causes like Croup are often treated with a single dose of oral steroids to reduce swelling. More severe cases may require inhaled treatments like nebulized epinephrine. If a foreign body is suspected or the condition is severe, surgical intervention to clear the airway may be necessary.