<Back Croup PLAIN LANGUAGE: The main sign of croup in children is a barking cough, caused by an infection that makes the throat swell up. This can be scary for both parents and children, but this handout explains what parents should do when their child develops croup, including home treatments, and tips on when parents should call the doctor or 911. Sign In Now To continue reading, you must be a subscriber to AAP Patient Education Online. Not a Subscriber? Subscribe Learn more about Patient Education Online Read the Sample Handout Take a Site Tour