A "wheeze" is a high-pitched whistling sound made when air flows through narrowed airways in the lungs, usually when someone breathes out (exhales).

More to Know

Wheezing is often caused by bronchiolitis, a common viral infection during the winter months. Asthma, allergies, infections, gastroesophageal reflux, and inhaled foreign objects are other common causes of wheezing.

Infants and children sometimes develop wheezing when they have a cold or other respiratory infection, but it doesn't necessarily mean that they'll develop asthma. Many infants who wheeze during their first 3 years of life outgrow it later in childhood.

Sudden wheezing can occur if a child accidentally inhales a foreign object (such as a peanut, coin, small toy, or piece of popcorn) into the airway. Wheezing that develops slowly is more likely to be caused by an infection.

Keep in Mind

Wheezing is a common symptom of asthma, although it can have other causes. Repeated episodes of wheezing might be a sign of asthma, especially if there is a family history of asthma, eczema, or allergies. Be sure to talk to your health care provider if your child has wheezing.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.