Croup is a viral infection of the voice box (larynx) and windpipe (trachea). Swelling of the vocal cords cause hoarseness, and children with croup may also have a tight, low-pitched "barking" cough.

Stridor occurs as the opening between the vocal cords becomes narrower. This is a high-pitched, squeaking sound heard when your child breathes in, and may be more obvious with crying or coughing. As the disease becomes worse, stridor may be heard even when your child is asleep or relaxed.

Expected Course

Croup usually lasts for 3 to 7 days, and the symptoms are worse in young children under 3 years of age.