Conditions + Treatments

Croup Symptoms & Causes

LIke ThisLIke ThisLIke ThisLIke ThisLIke This

Contact the Center for Airway Disorders

What causes croup?

Croup can be caused by a variety of different viruses. The most common is the parainfluenza virus, but others may include:

Your child may become infected through direct contact with a person, or through the secretions of another person who is infected with the disease. The infection begins in the upper respiratory tract and then slowly spreads down the tract (unlike a cold, which stays in the upper respiratory tract). Swelling affects the area around your child’s larynx (voice box) and into the trachea (windpipe).

Younger children are more affected by croup because their airways are smaller. Therefore, a small amount of swelling can cause a large amount of obstruction in their airways.

What are the symptoms of croup?

Keep in mind that each child may experience symptoms differently. As the disease progresses down your child’s respiratory tract, the symptoms can change and may include:

  • runny nose, congestion, and slight cough
  • cough develops into a seal's bark
  • laryngitis
  • fever
  • stridor

Very often, the symptoms are worse at night and may wake your child from sleep. Symptoms also seem to improve in the morning and get worse as the day goes on.

The symptoms of croup may resemble other conditions and medical problems. Always consult your child's physician for a diagnosis.

How long will my child be sick?

The extent of the disease varies for each child, but most children improve in three to seven days.

We are grateful to have been ranked #1 on U.S. News & World Report's list of the best children's hospitals in the nation for the third year in a row, an honor we could not have achieved without the patients and families who inspire us to do our very best for them. Thanks to you, Boston Children's is a place where we can write the greatest children's stories ever told.”
- Sandra L. Fenwick, President and CEO

Boston Children's Hospital
300 Longwood Avenue, Boston, MA 02115
For Patients: 617-355-6000
For Referring Providers: 844-BCH-PEDS | 844-224-7337