Stridor: Is Noisy Breathing Something to Worry About?

Noisy breathing can be common, especially when you have an upper respiratory infection. Although it’s not usually dangerous, it can be frightening. Stridor is a specific high-pitched breathing sound that’s sometimes serious. In certain cases, stridor can be life-threatening and may need urgent medical attention. 

Stridor is most common in infants and young children, but it can also occur in adults. The causes vary widely, and it can come on suddenly or be long term. Let's take a closer look at stridor, what causes it, and how we treat it.

What causes stridor?

Stridor is due to narrowing of the upper airway. This changes airflow and creates a telltale high-pitched sound. The location of the narrowing determines the type of sound you hear. You may hear the sound when breathing in (inhaling), breathing out (exhaling), or both. 

Swelling of the airway or something pressing on the airway can cause stridor. This can come from conditions that are:

• Congenital (present at birth)

• Infectious (caused by infection)

• Noninfectious (caused by conditions like allergic reactions, acid reflux, tumors, etc.)

Congenital causes

Stridor can be due to a narrowing of the upper airway that’s present at birth. Common causes include:

• Laryngomalacia: This is the most common cause of stridor in infants. It occurs when the upper airway (larynx) is too soft and collapses during breathing.

• Subglottic stenosis: This occurs when the cricoid cartilage of the larynx becomes rigid and narrow. It may be congenital but can also happen after having a breathing tube for a long period of time.

• Subglottic hemangioma: This is a mass of blood vessels under the vocal cords. It can cause narrowing and stridor. 

• Vascular ring: Some infants are born with a blood vessel that wraps around the windpipe. This can constrict the airway.

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Infectious causes

Infectious causes of stridor often involve fever, sore throat, congestion, or cough. Common infections that lead to stridor include:

• Croup: This viral infection often occurs in young kids. It causes stridor due to airway inflammation. It’s common to have cold symptoms, a barky cough, sore throat, and a hoarse voice. 

• Epiglottitis: This is when the epiglottis (a piece of cartilage at the back of the tongue) swells due to infection. Haemophilus influenzae type b (Hib) infection is the most common cause of this serious condition. The Hib vaccine prevents most cases.

• Retropharyngeal abscess: A throat infection can sometimes cause a large pocket of pus. This can block the airway.

• Bacterial tracheitis: This is a rare bacterial infection of the trachea. It can lead to inflammation and swelling.

Noninfectious causes 

There are other common causes of stridor that do not involve an infection. These can include:

• Foreign bodies: An object can lodge in your upper airway if you accidentally inhale something. This may happen with food or another object.

• Anaphylaxis: Severe allergic reactions can lead to symptoms that affect the whole body. This can include hives, nausea/vomiting, and airway inflammation. 

• Angioedema: This condition involves swelling in the deeper layers of the airway tissues. An allergy or medication side effect is often the cause. But in some cases it’s due to a genetic cause or an unknown reason. 

• Acid reflux: This can lead to inflammation of the upper airway. It may also cause a barky cough and sore throat.

• Vocal cord paralysis: Your vocal cords allow you to speak. But they also close to protect your airway from water, food, or saliva. And they open so you can breathe. Paralysis can occur from neurological damage, viral infections, or cancers affecting the throat.

• Laryngospasm: The vocal cords intermittently spasm and close. Vocal cord dysfunction results in difficulty breathing and stridor. The spasm is usually brief and resolves on its own. But it may recur. Triggers can include exercise, anxiety, or acid reflux.

• Tumor: Tumors of the head and neck that develop in the throat can compress the airway.

What other symptoms may occur with stridor?

Along with noisy breathing, there are sometimes other symptoms with cases of stridor. The symptoms can vary and depend on the cause of the stridor. 

Congenital causes

Congenital causes of stridor generally develop during infancy. There may not be any other symptoms. But in severe cases, there may also be:

• Feeding problems

• Swallowing problems

• Apnea (a pause in breathing)

• Failure to thrive (slow physical growth)

Infectious causes

When there’s a fever with stridor, it points to an infection as the most likely cause. Viral croup is the most common, but in rare cases there’s a more severe bacterial infection. 

Other common symptoms of infectious stridor include:

• Sore throat

• Unwell feeling

• Barky cough

• Drooling

• Lethargy

Noninfectious causes

Without fever or other signs of illness, a noninfectious cause of stridor is more likely. Symptoms may include:

• Barky cough

• Voice changes

• Difficulty swallowing

• Hives

• Vomiting

What is the difference between stridor and wheezing?

It’s easy to confuse stridor and wheezing, since they’re both abnormal breathing sounds. But there are a few differences to help identify your symptoms.

Stridor is a harsh, high-pitched sound that you can often hear without a stethoscope. You usually hear stridor when inhaling. But, in some cases, you can hear it while exhaling. In babies and children, stridor worsens when they’re agitated or crying. 

Wheezing is a whistling sound during exhaling. And it usually requires a stethoscope to hear. Sometimes it’s associated with a coarse rattling sound. Wheezing is usually associated with asthma or anaphylaxis. 

How do you treat stridor?

Treatment for stridor varies greatly and depends on the cause. Your healthcare provider will figure out the best treatment plan for you. It may include:

• Corticosteroids: These medications can help to decrease inflammation and swelling. It’s a common treatment for children with croup.

• Epinephrine: Epinephrine is an important treatment for anaphylaxis. It’s also used in other cases of stridor, such as croup.

• Antihistamines: These medications can help if there’s an allergic reaction. This can help treat anaphylaxis or angioedema.

• Laryngoscope: Treatment may involve placing a small camera to look down the throat. This can help diagnose vocal cord paralysis or allow your provider to see if there’s a foreign body. If a foreign body is causing your symptoms, the scope can help remove it.

• Antibiotics: If there’s a bacterial infection, treatment will include antibiotics. Antibiotics only treat bacteria and do not help with viral infections like croup.

• Surgery: Some conditions may need surgery to treat the cause of airway narrowing. This may be the case with some congenital causes, severe vocal cord paralysis, or a tumor. If there’s an abscess, your provider may use a procedure to create a small opening and drain the infection.

• Intubation: In rare cases of severe airway narrowing, intubation might be necessary. This involves inserting a breathing tube to help keep the airway open and to assist with breathing.

When should you be concerned about stridor?

Some cases of stridor are mild and resolve on their own. But other cases can be progressive and require more urgent treatment. So it’s important to let your provider know if you’re having any changes in your breathing.

Seek medical care emergently if you have: 

• Difficulty breathing

• Lethargy

• High fevers

• Drooling

• Bent-over posture to breathe 

• Possible anaphylaxis

If stridor is a new symptom, notify your healthcare provider. Untreated stridor that worsens can lead to severe breathing difficulty. And it may be life-threatening.

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Written by:

Louisa Salisbury, MD

Louisa Salisbury, MD, is a licensed, board-certified general pediatrician. She received a bachelor’s degree in human development from the University of California, San Diego, and obtained her medical degree from the University of Vermont Robert Larner College of Medicine.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

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