What Is Croup? The Causes, Symptoms, and Treatments to Know
Key takeaways:
Croup — also known as laryngotracheitis -— is usually caused by a virus that spreads widely among children every winter.
A barking cough is the most recognizable symptom of croup in babies and toddlers.
If you’re concerned about your child’s breathing, take them to an emergency room immediately.
Table of contents
The sound of a child with croup is hard to forget. The noisy, barking cough can be alarming, especially for parents hearing it in the middle of the night.
While the cough that comes with croup might sound scary, the illness itself usually passes without harm, especially for older children. Keep reading to get the real story on croup — what causes it, what you should do if you suspect your child has it, and when you should worry.
What is croup, and what are the symptoms?
Croup is a viral respiratory illness that causes:
A loud, barking cough, which is often worse at night
A runny or stuffy nose
Fever
Fussiness and poor appetite
In most cases, croup lasts only a day or two. During that time, symptoms might come and go.
Croup is most common in children between the ages of 6 months and 3 years. Children older than 4 might develop a noisy cough, but they usually don’t experience severe symptoms. This is because their airways are larger and less likely to get dangerously swollen.
What causes croup?
Croup is usually caused by a virus. About 75% of the time, that virus is parainfluenza, although other respiratory viruses — like respiratory syncytial virus (RSV), Rhinovirus, Enterovirus, and adenovirus — can also cause croup symptoms in children.
What’s that barking cough? Croup causes a unique cough that’s tough to forget once you’ve heard it. Learn how the sound of a cough can give you clues about your illness.
Baby Croup or RSV? Like croup, respiratory syncytial virus (RSV) is common during the winter months. Watch for breathing symptoms, especially in babies.
Adults can get croup, too. They can also get other childhood viruses, like the one that causes hand, foot, and mouth disease.
Although the name “parainfluenza” sounds a lot like influenza, it’s not related to the flu. That said, the flu does sometimes cause croup symptoms in babies.
When a child develops croup, the germ enters their body and causes swelling in their trachea (windpipe) and around their vocal cords (voice box). The swelling of the vocal cords is why the cough with croup is so noisy.
Sometimes, a croup-like cough can be caused by other things, like allergies or gastroesophageal reflux disease (GERD). When caused by allergies or GERD, the cough tends to occur over and over again without a fever or cold symptoms.
Read more like this
Explore these related articles, suggested for readers like you.
Can adults get croup?
Though it’s rare, it can happen. When adults do get croup, it can lead to serious illness. So, it’s important to prevent the spread if a child at home is sick with croup.
Is croup contagious?
The viruses that cause croup are contagious. They’re usually spread through respiratory droplets in the following ways:
Coughing
Sneezing
Talking
Viruses can also spread through close contact and by sharing items like cups, straws, and eating utensils. It’s important for anyone with croup to stay home and practice preventive measures to keep from spreading the illness.
How long is croup contagious?
Experts say the first 3 days are the most contagious, but someone with croup may be contagious for up to a week.
When to get medical care for a child with croup
If your child is showing signs of croup, you’ll want to watch them closely. While many children with croup do fine without treatment, there are times when emergency care is needed.
Some people find that croup tends to get worse at night. If your young child develops croup symptoms during the day, consider taking them to their pediatrician or primary care provider immediately for evaluation before the office closes for the evening.
Make an appointment at the doctor’s office during regular hours if your child:
Is breathing comfortably but has a sharp, loud, or barking cough
Has had croup symptoms for more than 2 days
At any time of day, the most important thing to notice is how your child is breathing. Children who aren’t upset should breathe in a quiet, relaxed way. If your child is crying, their breathing is probably pretty noisy. Try to calm them down first, and then listen. If you hear noises every time your child draws a breath, it’s called stridor, which is a concerning sign.
When to take your child to the emergency room
Seek emergency care if your child has croup symptoms and they:
Are relaxed but still make noises every time they draw in a breath
Seem uncomfortable or scared when they cough or breathe
Can’t draw enough air to talk or cry between coughs
Are drooling because they can’t swallow at all
Have a bluish tint around their lips or fingernails
What’s the difference between epiglottitis and croup?
Epiglottitis (swelling of the epiglottis) is different from croup. It’s severe, life-threatening swelling inside the airways that gets worse very quickly. Epiglottitis is most common in children aged 2 to 5 and is a medical emergency.
Fortunately, epiglottitis is rare these days because of the Hib vaccine. This vaccine protects against Haemophilus influenzae type B, the bacteria that causes it. And the vaccine is routinely given at 2, 4, and 6 months of age.
If your child hasn’t had their Hib vaccines, any breathing symptoms — especially drooling or stridor — should be taken very seriously. Make sure your child’s healthcare team is aware if your child isn’t protected against epiglottitis.
Can you test for croup?
There isn’t a specific test for croup. Most of the time, clinicians diagnose croup based on a child’s symptoms.
Sometimes, they can test for respiratory viruses, including parainfluenza, in their offices. But these tests don’t always give a clear answer when it comes to croup. If a child shows the typical symptoms of croup, their treatment will be the same whether they tested positive for a respiratory virus or not.
Why can getting an X-ray be helpful?
The swelling caused by croup can sometimes be seen on an X-ray of the neck and chest. Since a barking cough might sometimes be caused by something other than croup, an X-ray could be used to tell the difference.
An X-ray might help tell the difference between croup and:
A toy or piece of food stuck in the throat
A malformation, growth, or tumor pushing on the windpipe
Swelling in a different part of the airway, such as the epiglottis
How is croup treated?
Treatment for croup depends on how bad the symptoms are.
Treatment for croup in a medical office
When croup symptoms are bad enough to require treatment, you’ll want to get things started quickly. In many cases, a steroid medication such as dexamethasone (Decadron) can be given at your doctor’s office. This medication reduces swelling in the airway within a few hours.
A child with moderate or severe croup might need even faster results. Nebulized epinephrine, which is given as a vapor through a mask, can often open your child’s airway in just a few minutes. After receiving epinephrine, children need to be monitored very closely for several hours.
Treatment for croup in the hospital
Children with severe croup symptoms may need to be observed in a hospital overnight. They might not need additional treatment, but medical staff are available nearby if needed.
In the hospital, a baby or child with croup might need:
Oxygen
Intravenous (IV) fluids to prevent dehydration
Additional doses of steroids or nebulized epinephrine
Children with other medical conditions, such as asthma, might also need additional treatments.
Caring for croup at home
In the past, many people believed that wrapping their child in blankets and taking them outside to breathe cool, night air would help with croup. Although studies haven’t shown a benefit from cool air, the rest of the idea might not be completely wrong.
Croup can be scary for children and symptoms often improve when they feel calm and relaxed. Wrapping your child in cozy blankets and holding them in your arms can provide comfort. Other calming measures can also help soothe croup symptoms.
Over-the-counter medicines for croup
If your child is uncomfortable or has a fever, acetaminophen (Tylenol) is effective. Children older than 6 months old can take ibuprofen (Advil or Motrin) instead.
Experts don’t recommend over-the-counter (OTC) cough medications for viral croup, especially for children under 4 years old. Research shows these medications don’t work very well in young kids and can have side effects.
Frequently asked questions
Croup is contagious, so the best way to prevent it is to stay away from others who are sick.
Although there isn’t a vaccine for the most common cause of croup (the parainfluenza virus), getting a flu shot every year can lower your child’s chance of developing flu-related croup.
In many cases, a child with croup will start feeling better in 2 to 3 days. Sometimes, symptoms can linger for a week or two.
Yes, any viral respiratory illness can turn into pneumonia. But it’s rare for croup to cause pneumonia, as it doesn’t usually last long. Some people, including babies, are more susceptible to getting pneumonia, so it’s important to keep a close eye on them while they’re sick.
The bottom line
Croup is the common name for a throat infection that spreads easily between children during the winter months. When babies and young children have croup, they often develop a noisy cough that sounds like a seal barking and they can show signs of breathing trouble as well.
Although it’s unusual for croup to be dangerous for older children, croup can cause real problems for young children and babies. If you’re ever worried about your child’s breathing, seek emergency care right away.
Why trust our experts?
References
Bjornson, C. L., et al. (2013). Croup in children. Canadian Medical Association Journal.
Gates, A., et al. (2018). Glucocorticoids for croup in children. Cochrane Database of Systematic Reviews.
HealthyChildren.org. (2009). Epiglottitis. American Academy of Pediatrics.
HealthyChildren.org. (2024). Croup in young children. American Academy of Pediatrics.
National Heart, Lung and Blood Institute. (2022). Pneumonia–causes and risk factors.
Neto, G. M., et al. (2008). A randomized controlled trial of mist in the acute treatment of moderate croup. Academic Emergency Medicine.
NHS Inform. (2024). Croup.
Smith, D. K., et al. (2018). Croup: Diagnosis and management. American Family Physician.
Vassilev, Z. P., et al. (2009). Safety and efficacy of over- the-counter cough and cold medicines for use in children. Expert Opinion on Drug Safety.
