What Is It?
Croup is a common respiratory illness in children that causes a change in breathing with a hoarse voice and a brassy, barking cough. Doctors sometimes call croup laryngotracheitis because it usually involves inflammation of the larynx (voice box) and trachea (windpipe).
Croup often is divided into two broad categories:
Infectious croup is caused by an infection with a virus, bacterium or other germ. In the United States, most cases of croup are caused by a virus. These infections usually occur in the fall and winter when people spend more time indoors.