Croup is caused by viral infections such as:

  • Parainfluenza
  • Influenza virus type A and B
  • Adenovirus
  • Respiratory syncytial virus (RSV)
  • Enterovirus
  • Rhinovirus
  • Coronavirus
  • Echovirus
  • Human bocavirus

Risk Factors

Croup is most common in kids between 6 months and 3 years of age. Kids this age have a smaller airway. Croup is also more common in the fall and early winter months.

Other things that may raise the risk are:

  • Having an upper respiratory infection
  • Not having needed vaccinations



The first symptoms may be like a common cold. They often happen at night. A child may have:

  • Cough spasms or hoarseness
  • A cough that sounds like a barking seal
  • Fever
  • Problems breathing
  • A harsh, high-pitched sound when the child breathes in, especially when crying or upset
  • Drooling and problems swallowing
  • Decreased alertness
  • Bluish color of nails, lips, or around the mouth


The doctor will ask about the child's symptoms and health history. A physical exam will be done. This is often enough to make the diagnosis.



The goal of treatment is to help the child breathe until the infection is gone. The infection often goes away in a week. Things like fluids and warm, moist air can help with breathing.

Children with severe symptoms may need a breathing tube put in the throat to help open the airway. This is rare.


Medicine may be needed to help the symptoms. The doctor may advise:

  • Over the counter medicine to lower fever and ease discomfort
  • Steroids to reduce swelling in the airways
  • Epinephrine to ease swelling until steroids start to work
  • Oxygen therapy for severe breathing problems


The risk of croup can be lowered by:

  • Washing hands often
  • Making sure a child's vaccines are up to date

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.