What is wheezing? Wheezing is a high-pitched, musical noise that occurs during breathing, when air flows through bronchial (breathing) tubes that are narrowed or partially obstructed. Wheezing is a continuous (defined as longer than 250 msec), coarse, whistling or “accordion-like” sound.

What causes wheezing? The potential causes for wheezing are many. The most common cause is asthma, but “not all asthma patients wheeze and not everyone who wheezes has asthma.” Any condition that causes a narrowing of the airway caliber, including bronchospasm, edema, tumor, secretion, foreign body, external compression, or dynamic compression, can produce wheezing. Even healthy people can produce wheezing if exhaling hard enough.

More common causes for wheezing include:


  1. Asthma
  2. Emphysema/COPD
  3. Pneumonia/pneumonitis
  4. Tracheobronchitis
  5. Bronchiolitis
  6. Foreign body in the lungs (aspiration)
  7. Smoking
  8. Heart failure/pulmonary edema (“cardiac asthma”)
  9. Severe allergic reaction (anaphylaxis)
  10. Medication-induced bronchospasm
  11. Vocal Cord Dysfunction
  12. GERD
  13. Certain viral infections

Less common causes of wheezing include:

  1. Tracheo-bronchial tumor
  2. Aortic aneurysm
  3. Carcinoid
  4. Tracheal stenosis
  5. Post-radiation stenosis
  6. Tracheomalacia
  7. Amyloid deposition
  8. Sarcoidosis
  9. Post-lobectomy

What are the characteristics of wheezing? Wheezing is usually most noticeable during exhalation. This usually results from significant reduction of expiratory flow rates (how well you can quickly exhale). On the other hand, inspiratory wheezing often signifies permanent airway stiffness (such as from stenosis, scar tissue, or tumor) or foreign bodies. The location of wheezing may also aid in the diagnosis. For example, wheezing heard all over the chest is more likely due to underlying diffuse lung condition, whereas localized wheezing suggests a more localized process, such as tumor or foreign body obstructing an airway. Wheezing is usually louder than the underlying breath sounds and can sometimes be heard without a stethoscope.

When do I call the doctor? You should call your doctor right away if you have:

  • Wheezing for the first time
  • Wheezing accompanied by shortness of breath, chest pain, bluish discoloration of the lips or nails, altered mental status or confusion
  • Wheezing caused by allergic reaction, including insect bite or sting, food, or medication
  • Wheezing that keeps occurring without explanation
  • Wheezing associated with swelling of the face, tongue or lips

If wheezing is severe or occurs with severe shortness of breath, you should go directly to the nearest emergency room.

What will happen at the doctor’s office? Your doctor should take a detailed history and then perform a physical examination, particularly of the head & neck, lungs, and heart.  Additional testing might include chest x-ray, breathing tests, and blood work (including arterial blood gases). Your doctor may prescribe drugs to relieve narrowing of the airways. You might require hospitalization.

Where can I learn more?

National Institutes of Health
European Respiratory Journal reprint on wheezing