Breathe overview

Wheezing is a high-pitched whistle that can occur in some lung and medical conditions when you breathe. This is common, and sometimes wheezing is a sign of a medical emergency. You may have wheezing without other symptoms, or you may also have other symptoms, such as shortness of breath. There are many possible causes, such as asthma and allergies. You need to accurately diagnose the cause of wheezing in order to receive effective treatment.


Wheezing can occur during inhalation (inhalation) and exhalation (exhalation), but expiratory wheezing is more common. Most people think of asthma when they hear wheezing, but other causes need to be considered as well.

Sometimes people have more than one condition that causes wheezing.


It’s important to know if the sound you hear in your lungs is actually wheezing. Why? Because there are other sounds that could be mistaken for wheezing.

During your physical exam, your healthcare professional will auscultate (listen to) your lungs for sounds as you breathe.

Your lungs may sound normal on auscultation, with quiet air moving in and out, or you may hear sounds that indicate a medical problem – such as wheezing crackles or stridor.

It’s important to distinguish between stridor, another serious symptom that usually has a different tone and is caused by different conditions. Both of these sounds can be signs of a life-threatening medical emergency.

Types of normal and abnormal breath sounds

wheezing and stridor

A gasp is usually a medium-pitched sound that is loudest when exhaling. It has a fairly continuous musical sound, including multiple notes.

The wheezing sound is produced by the narrowing of the airways. This can be due to swelling or blockage anywhere from the throat to the smallest airway.

You may mistake stridor for wheezing.

Some differences between the two:

  • Stridor’s sound is usually monophonic – meaning only one note is heard rather than various notes.
  • The stridor is often higher in pitch than the wheeze.
  • Stridor occurs mainly during inspiration.
  • Wheezing is usually loudest in the front of the neck, while wheezing may be loudest in the lungs.
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The most common causes of wheezing are asthma and chronic obstructive pulmonary disease (COPD), but there are many potential causes, including:

  • Allergic reaction: This medical emergency is a severe allergic reaction (usually caused by a bee sting, medication, or eating nuts or shellfish) that causes a swollen throat.
  • Bronchitis: This can be acute (lasting only a few days) or chronic (lasting weeks to months to years).
  • Bronchiolitis: This is an infection that involves the bronchioles (the smallest airways) and is most common in children. It is usually caused by respiratory syncytial virus (RSV).
  • Inhalation (inhalation) of a foreign body: Choking can sometimes cause wheezing if the inhaled object does not completely block the airway. Wheezing associated with inhaling a foreign body is usually on one side of the chest.
  • pneumonia
  • Bronchiectasis: Dilation of the airways, usually due to childhood infection or cystic fibrosis, is another cause of wheezing. While cystic fibrosis is most often diagnosed in early childhood, it is also sometimes diagnosed in adulthood.
  • Viral infections: Many viral infections can cause wheezing, especially in children.
  • Lung cancer: A tumor blocking the airway can cause wheezing.
  • Heart failure: This can cause fluid to build up in the lungs.
  • Pulmonary embolism: A blood clot in the leg may rupture and enter the lung, rarely causing wheezing.
  • Acid reflux: This may not seem obvious, but acid reflux is a fairly common cause of wheezing.
  • Hypersensitivity pneumonitis: Chronic inflammation of the lungs from things like moldy hay and bird droppings can cause wheezing.
  • Medications (especially aspirin)
  • Vocal cord dysfunction: Caused by the inadvertent closure of one or both vocal cords during breathing. This is also known as “vocal cord asthma.”
  • Epiglottitis: A medical emergency characterized by symptoms such as fever, drooling, and trying to breathe in an upright position, epiglottitis is caused by an infection of the epiglottis, the small piece of cartilage that attaches to the end of the tongue. Epiglottitis usually causes stridor to be heard in the neck, but can also cause wheezing.


It is important to see your healthcare professional if you have been wheezing or your symptoms have changed—even if you have experienced wheezing in the past or have been diagnosed with asthma.

Get emergency medical help if you experience chest pain, dizziness, shortness of breath, blue lips and skin, or swelling of your face, neck, or lips.


The first thing your doctor will do is make sure you are comfortable and stable. In an emergency, medical staff and technicians start with “ABD”. This represents the airway, breathing, and circulation. It’s important to evaluate these before moving on to try to determine what’s really causing the wheezing.

Once you are stable, your medical team will discuss your medical history with you and perform a physical examination.

Some questions they might ask you include:

  • When did your symptoms start?
  • Have you had symptoms like this before?
  • Did you choke while eating?
  • Have you ever been stung by a bee, or have you eaten food that can cause a severe allergic reaction, such as shellfish or nuts?
  • Do you have any other symptoms, such as cough, shortness of breath, chest pain, hives, swelling of your face or neck, or coughing up blood?
  • Is your wheezing worse at night or during the day?
  • Do you have a personal or family history of asthma, eczema, lung disease or lung cancer?
  • Do you, or have you ever, smoked?

Your physical examination will usually begin with measuring your vital signs, oxygen levels, and auscultation of your lungs and heart.


The tests to assess your wheezing and determine the cause will vary based on your medical history and physical examination.

Tests may include:

  • chest x-ray
  • Spirometer
  • blood tests, such as white blood cell counts to look for signs of infection
  • Pulmonary function tests
  • chest CT scan
  • Do a bronchoscopy if your healthcare provider is concerned that you may have inhaled (inhaled) a foreign object or that you may have a tumor in or near your airways
  • Laryngoscopy to examine your larynx and vocal cords
  • Allergy testing if your doctor thinks your allergies are causing your airways to spasm


Depending on the severity of your symptoms, your healthcare provider will first take the necessary steps to make you comfortable and manage your symptoms. Since there are many possible causes of wheezing, further treatment will depend on the cause of your wheezing.

The first step is to make sure your lungs are getting enough oxygen. Oxygen therapy is commonly used. If the wheezing is caused by an allergic reaction, injections of epinephrine are usually given.

Other treatments will depend on the underlying cause of the wheezing. For example, asthma treatment will be used to open the airway, while surgery such as bronchoscopy may be recommended if a foreign body is thought to be blocking the airway.

VigorTip words

There are many reasons for wheezing. An asthma attack can be life-threatening. The treatment of asthma has advanced significantly over the past few decades, and many people are able to lead relatively normal lives despite the disease. In the case of a life-threatening asthma attack called state asthma, intravenous medications, intubation, and extracorporeal membrane oxygenation (ECMO) may be required.