Wheezing: Causes and Risk Factor

What does it mean if I hear wheezing?

Patient consulting Doctor for breathing difficulties, Asthma
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In This Article

Emitting a whistle-like sound when you breathe is the result of air moving through narrowed airways. Asthma is the most common reason for this narrowing and the wheezing sound you might hear as you breathe. However, it's not the only possible cause. Wheezing could be a sign of numerous conditions—some minor health issues, some extremely serious. The most important thing to keep in mind is that wheezing is never normal. If you hear a high-pitched sound when you inhale or exhale, you should consult a doctor to find what is blocking your airway.

Common Causes

When your airways narrow, your breath has difficulty moving through your lungs. The obstruction leads to a whistling noise as air is forced through the pathways into and out of your lungs. This narrowing (also referred to as a blockage or obstruction) usually occurs in the small bronchial tubes, but in some cases, it may be caused by problems with the larger airways (including the trachea or bronchi) or the vocal cords.

A number of issues can create an obstruction in your airways. Three of the most common are asthma, COPD, and vocal chord dysfunction.


Most wheezing is related to bronchial asthma. Specifically, wheezing occurs in what is called the "yellow zone" of the disease (the middle range, when the disease is getting worse but before it becomes a serious medical issue). At that point, wheezing is often accompanied by other typical symptoms of asthma, including:

There are many different types of asthma and many different ways for the chronic lung disease to manifest, but studies show that of those who have symptoms consistent with any type of asthma more than 53% have a history of wheezing.

Chronic Obstructive Pulmonary Disease (COPD)

An inflammatory disease of the lungs, COPD is a progressive disease in which the lungs become increasingly inflamed. This leads to symptoms such as a persistent cough, excessive phlegm, tightness in the chest, shortness of breath, and wheezing.

These symptoms may not be noticeable in the early stages of COPD, but they become more severe as the disease progresses

Vocal Chord Dysfunction

Also called paradoxical vocal fold motion, vocal chord dysfunction (VCD) is characterized by wheezing caused by an abnormal closure of the vocal chords. Other symptoms may include shortness of breath and chest or neck tightness. VCD's symptoms are so similar to asthma that it is sometimes called vocal cord asthma.

While the causes of VCD are still not completely clear, it seems to be related to post-nasal drip, complications of asthma, and laryngopharyngeal reflux (in which stomach acid travels up the esophagus and irritates the larynx). Psychological factors are also thought to play a role in VCD in some patients.

After the World Trade Center attacks in 2001, there were increased incidences of VCD among 9/11 first responders, which is believed to have been a result of the workers inhaling dust and chemicals at Ground Zero.

To different degrees, you can manage asthma, COPD, and VCD.

  • Asthma can be well controlled with proper care. In the case of childhood asthma, children tend to "grow out of it." Symptoms cease with no lingering effects.
  • With COPD, there is no cure for the irreversible damage to the lungs. While symptoms can be managed, the disease will continue to progress and become more debilitating with time.
  • VCD can be treated with speech therapy or breathing exercise, or by treating underlying causes such as reflux, allowing wheezing and other symptoms to go away.

Less Common Causes

Various types of infections and allergic reactions can all cause pulmonary obstructions that result in wheezing. These illnesses include

  • Structural abnormalities: This includes enlarged tonsils or adenoids that can obstruct breathing in children when they become infected. In studies, 36% of children with chronic wheezing had some kind of structural abnormality. Anatomic problems might also include a lung cyst or tumor.
  • Allergies: Wheezing that occurs after eating certain foods, being bitten by an insect, or having been exposed to an allergen is the sign of an allergic reaction. Anaphylaxis is a severe allergic reaction that can lead to the sudden onset of wheezing. It's a potentially life-threatening emergency that requires immediate treatment.
  • Parainfluenza: Unrelated to the flu, parainfluenza actually refers to a group of viruses that cause upper and lower respiratory infections. Some of these result in wheezing, including bronchitis, bronchiolitis, and pneumonia.
  • Cystic fibrosis: Cystic fibrosis is a congenital disease that results in poor growth in childhood, weight problems, cough, and shortness of breath. Approximately 61% of children with cystic fibrosis experience wheezing associated with underlying respiratory problems in the first 6 years of life.
  • Foreign body: Small choking hazards such as coins, beads, or small candy can be lodged in in the trachea and cause wheezing.
  • Bronchospasm: This is a sudden narrowing of the airways that is common with asthma, but it can also be caused by other illnesses, exercise, a sudden intake of cold air, exposure to smoke, anesthesia, and other irritating conditions.
  • Gastroesophageal Reflux Disease (GERD): While GERD can be a cause of worsening asthma, GERD can also lead to less common causes of wheezing from recurrent pneumonia or scarring of the lungs.
  • Pulmonary embolism: A pulmonary embolism is a blood clot in the lungs. Wheezing may be one of several symptoms, but patients more commonly have acute shortness of breath and chest pain.


Wheezing is related to a variety of complicated disorders. Some of these have genetic components, and you may be at greater risk if you have a chromosomal mutation.


Allergic asthma, which accounts for 60% of asthma, is known to be an inherited disorder. Doctors don't understand the inheritance pattern at this point, but they know that the condition itself is not passed down. Instead, a genetic mutation that increases the risk of allergic asthma, is inherited. Not all people with the mutation will develop asthma, though. Other factors come in to play which will lead to asthmatic symptoms being manifested.

COPD and Emphysema

A genetic disorder called alpha-1-antitrypsin (AAT) deficiency causes lung damage that leads to leads to COPD and emphysema. With this inherited condition, your body doesn't make enough of the protein AAT, which normally would stop a powerful enzyme that destroys dead cells in the lungs. Without enough AAT, the enzyme starts destroying healthy cells, and the small air sacs in the lungs (alveoli) are damaged.

The earliest symptoms of ATT deficiency, which usually manifest between ages 20 and 50, include shortness of breath, reduced ability to exercise, and wheezing.

Cystic Fibrosis

Cystic fibrosis is one of the more common genetic diseases. Frequency varies by ethnic background, affecting one in 2,500 to 3,500 white newborns, but only one in 17,000 African Americans and one in 31,000 Asian Americans.

CF is an autosomal recessive disorder, meaning that you need to inherit the CFTR mutation from both your mother and father to have the disease. If you only inherit one defective gene, you won't have CF but will instead be a carrier of the mutated gene.

Tracheoesophageal Fistula

A very rare, non-inherited birth defect, tracheoesophageal fistula is a structural problem that causes wheezing. Babies with this condition are born with abnormal connections between the esophagus (the tube that leads from the throat to the stomach) and the trachea (the tube that leads from the throat to the windpipe and lungs).


Wheezing can also be due to a build-up of fluid in the lungs, which results from congestive heart failure (CHF). With CHF, the heart cannot adequately pump blood through the body. The blood that can't get pushed forward backs up in the veins, and fluid leaks into the lungs. Along with the wheezing, you may have a persistent cough that produces blood-tinged mucus.

Lifestyle Risk Factors

Genetics and infection play a significant role in disorders that cause wheezing. However, there are several factors directly in your control that can lower your risk for conditions that cause breathing difficulty. These include

  • Cigarette smoking
  • Exposure to secondhand smoke
  • Exposure to chemicals
  • Indoor and outdoor air pollution

These factors can trigger serious illnesses such as cancerous tumors or COPD. In other instances, they cause spontaneous breathing problems that pass once the irritant is removed. For instance, hypersensitivity pneumonitis is a condition that results in chronic exposure to certain substances called antigens, such as moldy hay and bird droppings. The wheezing generally stops once the antigen is no longer present.

A Word From Verywell

Because wheezing is never part of normal breathing, you should always seek medical advice if you start to develop a wheeze and don't have a clear understanding of the cause. However, first, be sure what you are hearing is actually a wheeze. Some children's diseases, such as croup, result in a "stridor" cough, which is often described as the sound a seal makes. Nasal congestion can also result in a sound that mimics a wheeze but isn't. If you recognize the sound to be a wheeze, see your doctor if you've never had problems wheezing before or if an existing wheeze is becoming more pronounced and frequent.

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