Duke Medicine: Bronchiolitis in children

Whenever winter looms on the calendar, many parents begin to worry that if their infants get colds, they will have trouble breathing. How can we tell when a common cold has progressed to something that needs more attention?

Bronchiolitis is an infection of the small airways in the lungs called “bronchioles.” The bronchioles are tiny tubes that carry air in and out of the lungs. In bronchiolitis these tubes becomes swollen, irritated, and blocked with mucous, making it difficult for the air to move smoothly in and out of the lungs.

Bronchiolitis occurs in children under two years of age. Young children have smaller airways than older children and adults, making them more susceptible to the breathing difficulties that occur with this infection.

Bronchiolitis is most commonly caused by respiratory syncytial virus (RSV), but can also be caused by a host of other common respiratory viruses. Because these viruses tend to circulate in the winter months, bronchiolitis typically occurs from November through March in North America. There is no evidence of a bacterial cause for bronchiolitis.