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This information was reviewed and approved by Franziksa J. Rosser, MD, MPH (11/30/2016).

What Is Croup?

Croup is a viral infection that usually affects infants and children between the ages of 3 months to 6 years.

It is more common in boys than girls. Croup often follows a cold, although croup may begin without cold symptoms. This illness is most often seen in the fall and winter. Croup may recur during childhood, but attacks tend to disappear as the child grows.

Croup is more a symptom than a diagnosis. Croup involves inflammation and swelling of the subglottic space (the area directly below the vocal cords in the throat area). Croup can be caused by a variety of viral infections, including parainfluenza, influenza (H1N1 and seasonal forms), respiratory syncytial virus (RSV), rhinovirus and a variety of other childhood respiratory viruses. Therefore it is possible, for example, for your child to "have" both croup and influenza.

Another condition called recurrent croup or spasmodic croup may not be caused by infection and is often managed by pediatric lung specialists. Children with this condition often present with numerous episodes of croup-like cough which are short-lived and not associated with other signs of respiratory infection. Children typically outgrow these symptoms, but medical evaluation may be important to determine the correct diagnosis.