Diagnosis

Doctors can usually diagnose croup by looking for the telltale barking cough and stridor, the squeaking sound on inhaling. They will also check the child for fever, cold symptoms (like a runny nose), or a recent viral illness, and ask questions to find out if the child has a prior history of croup or upper airway problems.

If the child's croup is severe and slow to respond to treatment, a neck X-ray may also be taken to rule out any other reasons for the breathing difficulty, such as a foreign object lodged in the throat or epiglottitis (an inflammation of the epiglottis, the flap of tissue that covers the windpipe). Typical findings on an X-ray if a child has croup includes the top of the airway narrowing to a point, which doctors call a steeple sign.