Wheezing is a high-pitched whistling sound made while breathing. It’s often associated with difficulty breathing. Wheezing may occur during breathing out (expiration) or breathing in (inspiration).
Inflammation and narrowing of the airway in any location, from your throat out into your lungs, can result in wheezing.
The most common causes of recurrent wheezing are asthma and chronic obstructive pulmonary disease (COPD), which both cause narrowing and spasms (bronchospasms) in the small airways of your lungs.
However, any inflammation in your throat or larger airways can cause wheezing. Common causes include infection, an allergic reaction or a physical obstruction, such as a tumor or a foreign object that’s been inhaled.
All of the following conditions can lead to wheezing:
Allergies
Anaphylaxis (a severe allergic reaction, such as to an insect bite or medication)
Asthma
Bronchiectasis (a chronic lung condition in which abnormal widening of bronchial tubes inhibits mucus clearing)
Bronchiolitis (especially in young children)
Bronchitis
Childhood asthma
COPD
Emphysema
Epiglottitis (swelling of the "lid" of your windpipe)
Foreign object inhaled
GERD (gastroesophageal reflux disease)
Heart failure
Lung cancer