Health Topics A-Z

What Is Croup?

Croup, a viral infection of the voice box (larynx) and windpipe (trachea) associated with signs of a respiratory infection, such as a runny nose or cough, is a relatively common ailment of childhood.

Usually the first indication is a cough that sounds like the bark of a seal. Your child may have trouble breathing because the tissue around the larynx is inflamed, constricting the windpipe, and because the bronchial passages are blocked with mucus. The sound of air being forced through the narrowed airways may produce hollow raspy noises, or stridor, with each inhaled breath.

Croup lasts for five or six days and is highly contagious. It usually affects children between the ages of 3 months and 6 years (the average age is 2 years), whose small windpipes and bronchial passages are vulnerable to blockage.

Most cases are mild and can be managed at home. In severe cases or in the case of epiglottitis — an unrelated bacterial infection of the epiglottis (the tissue flap that covers the trachea when swallowing), whose symptoms mimic croup — your child may need to be hospitalized.

What Causes It?

Most croup cases are caused by a parainfluenza virus. The disease is transmitted by airborne droplets from an infected child's cough