Croup is a virus infection of the voice box (larynx) and windpipe (trachea) and usually affects children up to the age of 5 years. Croup often begins like a normal cold then the child develops a harsh, barking, croupy and cough - often at night-time. The voice is hoarse and the child may develop a noise when breathing in (stridor). The stridor is due to narrowing of the trachea caused by the virus infection. At first, the stridor may only be noticed when the child is active. Croup may last for 3-4 days.
