Overview of Bronchiolitis

Bronchiolitis is a viral infection that usually affects young children between the ages of 2 and 24 months. The infection affects the bronchioles, which are the airways that lead to the lungs. Bronchiolitis is highly contagious and is more common in the winter and early spring.

Bronchiolitis usually starts like a cold, but symptoms quickly become more serious. The bronchioles become inflamed and filled with mucus, causing severe coughing and difficulty breathing. Children are generally sick for 7 to 10 days, and often cough for a few more weeks. In severe cases, children who have bronchiolitis may require hospitalization.

Incidence and Prevalence of Bronchiolitis

About 20 percent of infants in the United States get bronchiolitis each year and 2–3 percent of these children require hospitalization. Children younger than 1 year of age are almost twice as likely to develop bronchiolitis as children between the ages of 1 and 2 years. Bronchiolitis is most common in children between 3 and 6 months of age.

Although bronchiolitis occurs throughout the year, it is more common in the winter. Peak incidence occurs in February. Bronchiolitis occurs more often in boys than in girls. The condition is more common in babies who are bottle fed and in children who live in crowded, urban areas. Some studies suggest that lower socioeconomic status may play a role and that children in this group may be hospitalized more frequently.

Worldwide, the rate of infection in developed countries is similar to those in the United States. Currently, there is not enough data to determine bronchiolitis rates in underdeveloped countries, but studies suggest that poor nutrition and sub-standard medical care may contribute to the condition in these areas. In tropical regions, bronchiolitis is more common during the rainy season.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 27 Aug 2008

Last Modified: 03 Sep 2015