Stridor vs Wheezing: Understanding Noisy Breathing

Noisy breathing, whether a high-pitched whistling or a wheezing sound, can be a sign of an underlying respiratory (breathing) issue. Two common types of abnormal breath sounds—stridor and wheezing—can indicate different problems in the airway, and distinguishing between them is crucial for accurate diagnosis and treatment. While stridor typically signals an obstruction or narrowing in the upper airway, wheezing often points to issues in the lower airway, like asthma or infections. This article explores the differences between stridor and wheezing, their causes, symptoms, and how they are treated, helping you understand when to seek medical care.

What Are the Four Respiratory Sounds? 

Normal lung sounds are soft and low-pitched sounds. They are also called bronchial lung sounds, vesicular lung sounds, and bronchovesicular lung sounds. Some are best heard when you breathe in, others when you breathe out. Your doctor can listen to your lung sounds by placing an instrument called a stethoscope on different parts of your chest wall - this is called auscultation. When your provider asks you to breathe in and out or take a deep breath during auscultation, the sounds help them assess how well your lungs function.

Stridor and wheezing are called adventitious lung sounds. They are heard in addition to normal lung sounds. Their presence can indicate problems in your lungs and airways. Other abnormal lung sounds include rales (crackles), rhonchi, and pleural rub.

What’s the Difference Between Wheezing and Stridor?

It’s important to differentiate between stridor and wheezing in adult and pediatric patients, as the latter can indicate the cause of noisy breathing. 

Note: Stertor is a common snoring sound heard in people who are congested. It can occur with the common cold, flu, allergies, and enlarged tonsils. Less commonly, it occurs due to a structural problem in the nasal cavity.

What is Stridor?  

Stridor is a medical term for noisy breathing. It stems from the upper airway and is a high-pitched whistling sound that can be heard when a person is breathing in or out. The most common cause of stridor is a foreign object stuck in the airway.

What Does Stridor Sound Like?

Stridor is an abnormal high-pitched, turbulent, whistling sound that can be heard during inhalation and exhalation. 

Common Causes of Stridor  

Stridor has several causes, such as: 

• An obstruction (blockage) by a foreign object   

• Infection of the upper airway, such as viral croup 

• Upper airway narrowing or inflammation (for example, tonsillitis, epiglottitis)

• Airway injury

What Does Stridor Breathing Indicate?

Besides the common causes listed above, other conditions that can cause stridor include:

• Scarring in the airway

• Cysts or abscesses 

• Tumors such as laryngeal cancer

• Problems with the voice box (larynx) or vocal cords, for example, vocal cord paralysis or vocal cord dysfunction

• Laryngomalacia is a condition in which the soft tissues cause partial airway obstruction, resulting in chronic stridor.

• Tracheomalacia (collapse of the trachea while breathing)

• Smoke or chemical inhalation

• Allergic reactions

• Neck surgery

• Certain congenital abnormalities of the heart

Is Stridor a Symptom of RSV?

Stridor is not a common symptom of RSV (respiratory syncytial virus). Wheezing is the main symptom and helps with the diagnosis of RSV.

What is Wheezing?  

Wheezing is also a type of noisy breathing. It stems from the lower airway and is a shrill whistling, coarse rattling, or squeaky sound when breathing out. A partial blockage in the airway, such as in people with asthma, causes wheezing.

What Does Wheezing Sound Like?

Wheezing is an abnormal high-pitched, musical, whistling, or purring sound that can be heard during exhalation. 

Common Causes of Wheezing  

Wheezing occurs due to a partial blockage of the lower airway.

What Does Wheezing Indicate?

Conditions that can cause wheezing include:

• Anaphylaxis (a severe allergic reaction)

• Allergies

• Viral or bacterial infections, including respiratory syncytial virus (RSV)

• Aspiration of a foreign object or substance into your lungs

• Asthma

• Chronic obstructive lung disease (COPD)

• Emphysema

• Bronchitis 

• Pneumonia

• Gastroesophageal reflux disease (GERD)

• Sleep apnea

• Congestive heart failure

• Smoking 

Wheezing vs Stridor: Key Symptoms and Indicators  

As mentioned above, abnormal breath sounds are heard when air flows through a blocked or narrowed airway. However, when you hear wheezing or stridor, you may be unable to tell the difference. You may also hear crackles (coarse crackles or fine crackles), which are different sounds with different causes. 

According to the American Family Physician, an accurate and timely diagnosis of a respiratory issue requires a thorough review of the patient’s history, a comprehensive physical exam, and evaluation of the respiratory tract (lungs and airways). 

For example, a healthcare provider can obtain clues about the location of the obstruction by differentiating an inspiratory stridor, which indicates a laryngeal obstruction, from an expiratory stridor, which indicates a tracheobronchial obstruction, or a biphasic stridor, which suggests subglottic or glottic abnormalities.

Impact on Breathing

The respiratory tract consists of the throat (pharynx), voice box (larynx), windpipe (trachea), airways (bronchi), and lungs. You inhale oxygen into your lungs and exhale carbon dioxide out of your body. This gives your body oxygen, which is necessary to survive.

The respiratory system produces sounds when air flows through larger airways and smaller airways and causes vibrations. When there is a narrowing or blockage in the airways, the sound produced during inhalation and exhalation changes, just like pressing a key on a trumpet changes the sound. 

Treatment and Management  

Stridor Treatment 

Treatment for stridor depends on the underlying cause. The goal is to remove the blockage in the airways. Treatment options include:

• Heimlich maneuver to dislodge an object stuck in the airway.

• Surgical removal of a foreign object.

• Medication to reduce inflammation and edema (swelling).

• Supplemental oxygen.

• Intubation (inserting a tube through the mouth or nose into the trachea to keep it open and allow air to flow).

• Tracheostomy (creating a surgical opening in the trachea through the neck to allow air to reach the lungs). 

Wheezing Treatment 

Treatment for wheezing depends on the underlying cause. The goal is to help you breathe more easily. Treatment options include:

• Oxygen therapy with supplemental oxygen.

• Certain medications, such as antibiotics, are used for bacterial infections.

• Bronchodilators (inhalers) for asthma.

When to Seek Medical Attention

Noisy breathing is not dangerous most of the time and resolves when an illness, such as an upper airway infection, resolves. 

But sometimes, it can be a sign of a serious underlying condition that is life-threatening and requires immediate medical attention—for example, a small object such as a coin stuck in a pediatric airway. 

A healthcare provider should evaluate any noisy breathing that does not quiet down or keeps returning. Do not assume it is a wheeze or stridor. Get it checked out by a medical professional. You should also seek emergency medical care when abnormal breath sounds are accompanied by other symptoms such as:

• Fast breathing

• Shortness of breath

• Chest pain

• Chest tightness

• Swelling of the lips or tongue

• Bluish discoloration of the skin or nails

• Confusion

Doctors in the emergency room or specialists, such as pediatric otolaryngologists, can diagnose the problem by performing tests such as bronchoscopy and laryngoscopy. These tests allow them to visualize the airways and determine what is causing airway obstruction.