You’ve probably heard of croup, right? It’s a frequent cause of cough in young kids during the fall and winter months. And it’s not an ordinary cough. The croup cough tends to be hoarse, similar to the sound of a barking seal. So what causes croup? What other symptoms are present? How do we treat croup, and can it be prevented? Let’s take a closer look.

The Cause

Croup is caused by a viral upper respiratory infection, which means antibiotics won’t help. Several viruses cause croup, but the most common is parainfluenza virus. This is different from influenza, so flu shots won’t prevent croup (but they are still a good idea to prevent the flu!). Parainfluenza causes swelling around the vocal cords, which results in the characteristic hoarseness and barky cough. Swelling may also extend down the trachea (windpipe) toward the lungs and impede the flow of air. This results in a faint, high-pitched sound with each breath in—a noise we call stridor. Stridor is more likely and severe in small children because they have a small-diameter airway that doesn’t take much swelling to obstruct airflow.


In addition to hoarseness, barky cough and the possibility of stridor, fever is common, along with other signs of a viral upper respiratory illness (nasal congestion, body aches, decreased appetite, less activity). Symptoms usually last about a week and are at their worst for 3-4 days before gradually improving. Fever lasting more than a couple days, moderate to severe cough, any amount of stridor or difficult breathing are reasons to call your child’s doctor.


As with any viral illness, the mainstay of treatment is supportive care: rest, plenty of fluids and fever-reducers as needed. When the barky cough is moderate to severe or if mild, intermittent stridor is present, one dose of steroid medicine (dexamethasone) is typically given.This lasts in the body a couple days, reducing airway swelling and improving airflow. Usually, one dose is enough and by the time it wears off, the viral illness is improving on its own. Occasionally, symptoms worsen as the steroid wears off, and a second dose is given.

When stridor is persistent or your child has difficulty breathing, epinephrine is given as an aerosolized breathing treatment. This is different than the breathing treatment given to kids with asthma and usually results in significant reduction of airway swelling. Epinephrine should only be given by a healthcare provider, and kids need to be watched following administration because sometimes swelling returns and is worse than before! This is called rebound. When rebound occurs, the affected child will need another breathing treatment and will likely be admitted to the hospital in anticipation of further treatments.

Prognosis & Prevention

Most kids with croup do fine and are better in a few days. However, kids with stridor or difficult breathing may go downhill fast, so it’s important to keep your child’s doctor informed of symptoms and seek help in an urgent care or emergency department if noisy or difficult breathing occurs. There are other conditions that cause stridor and difficult breathing, such as foreign body aspiration and other infections of the upper airway, making it even more important to seek help quickly.

Croup is difficult to prevent because the viruses that cause it are common wherever kids gather, especially in the autumn and winter months. The best prevention is to avoid contact with sick children and lots of hand washing!

If your child needs immediate medical attention, call 911 or visit your nearest Urgent Care or Emergency Department.

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Nationwide Children's Hospital Medical Professional
Mike Patrick, MD
Emergency Medicine; Host of PediaCast

Dr. Mike Patrick is an Assistant Professor of Pediatrics at the Ohio State University College of Medicine and Medical Director of Interactive Media for Nationwide Children's Hospital. Since 2006, he has hosted the award-winning PediaCast, a pediatric podcast for parents. Dr. Mike also produces a national podcast for healthcare providers—PediaCast CME, which explores general pediatric and faculty development topics and offers free AMA PRA Category 1 Credit™ to listeners.

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