Croup in Kids: What It Sounds Like, What Causes It, and When to Worry
When I was a resident, we used to say we could spot croup the moment a child walked into the waiting room: that seal-like barky cough gives it away every time.
But that cough is just one piece of what parents need to know about croup. Let’s break down what it is, what causes it, what to watch for, and what to do when your child sounds like a baby seal.
What is it?
Croup isn’t a specific virus. It’s a set of symptoms that happen when the upper airway (around the voice box and windpipe) becomes swollen and narrow.
That swelling makes it harder for air to pass through, leading to:
A hoarse voice
A classic barky cough (like a seal)
Sometimes a high-pitched sound when breathing in (called stridor)
Croup is most common in fall and winter and affects children under age 5 the most because their smaller airways make them more prone to breathing issues when swollen.
Why it matters
Most cases of croup are mild and just sound dramatic. But in young kids, even a little swelling can make it hard to breathe. Which means things can go south very quickly. That’s why it’s important to know the signs of trouble and when to call your pediatrician.
Symptoms
Barky seal-like cough
Hoarse voice
Stridor (high-pitched squeaky sound when breathing in)'
Runny nose or congestion
Fever (sometimes)
Vomiting or diarrhea (sometimes)
The Pediatrician Mom Tip: Croup often gets worse at night because lying down increases swelling and postnasal drip. Don’t be surprised if your child seems fine during the day and worse after bedtime.
Causes
The most common cause is a viral infection (usually parainfluenza virus, which is different from the flu). But croup-like symptoms can also happen with:
Allergies
Reflux
Anatomical differences (some kids just have smaller airways)
If your child gets croup with every cold, talk to your pediatrician: sometimes an ENT evaluation is helpful.
Is it contagious?
If the cause is viral then YES. Croup spreads through coughs, sneezes, and droplets, just like other respiratory viruses.
The incubation period (time from exposure to symptoms) is usually 2–7 days.
Good handwashing and keeping distance from sick contacts can help reduce spread.
Who’s at most risk?
Kids under 2 years
Kids with asthma or other lung / heart issues
Children with weak immune systems or low muscle tone
Older adults or those with chronic illness
How to treat croup at home:
Remember: this post is for educational purposes only. Because each child is different, it is important to talk with your child’s pediatrician if you are concerned about them. They can help you figure out if your child can be managed at home and review when to have them seen.
Croup can range from mild to severe. In mild cases, you may only hear a barky cough and no stridor (for examples of what stridor sounds like, click here).
If you hear stridor only when your child is upset or crying, you may be able to manage things using some of the tricks below while you wait for your healthcare provider to call you back. If you hear stridor even when your child is not upset, this can be an emergency.
For most children, however, croup symptoms are caused by an infection and the focus is often supportive care.
1. Keep them calm
Crying and panic can worsen the airway swelling.
Tip: Stay close, hold them, speak softly. calm kids breathe easier.
2. Try steam or cool air
Sit together in a steamy bathroom for 10–15 minutes.
Step outside into cool night air or open the freezer door; the cold air can help reduce swelling.
3. Focus on comfort
Your goal is to keep your child comfortable. This may involve snuggles, screentime, or medication. When kids have fevers, they usually breathe faster, which can make croup worse. Giving them a fever reducer like acetaminophen or ibuprofen may help.
Dosing for fever reducers is here.
4. Keep them hydrated
Yes. This is the cornerstone of most illnesses in kids. Push fluids, and know the signs of dehydration. Encourage fluids (popsicles, Pedialyte, smoothies, breastmilk and formula all count). More dehydration information here.
5. Watch breathing
Listen and look for:
Fast breathing
Increased work of breathing (eg: nasal flaring, retractions, head bobbing). More on this here.
Stridor (especially when resting)
If you hear stridor when your child is calm or asleep, go to the ER immediately.
The Pediatrician Mom Tip: If your child’s croup is caused by other issues, such as laryngomalacia or other airway abnormalities, or reflux, their treatment likely will depend on the cause.
When to Call Your Pediatrician
This is not a comprehensive list. In general, always call your pediatrician if you have any concerns about your child. There is a lot to be said for a parent’s gut instinct, and I promise: your pediatrician would rather you called!
Some concerning symptoms include:
Stridor (especially at rest)
Signs of difficulty breathing
Trouble swallowing, drooling, or very hoarse voice
Dehydration (no tears, dry mouth, fewer wet diapers).
Lethargy or difficult to wake
Is under 6–12 months old
Has recurrent croup (more than twice per year)
Any underlying medical conditions or risk factors
If your child is not improving as expected, or seems to be getting worse, even if they’ve already been seen
Anything else tickling your spider sense! Trust your gut!
What to expect at the doctor’s office
Your pediatrician or ER doc may:
Give steroids (oral or IV) to reduce airway swelling
Provide a breathing treatment (racemic epinephrine) in more severe cases. This is not the same medication that we use for asthma. If your child needs this, they usually will be on a monitor and need to be observed afterwards in the ER.
Recommend IV fluids if your child isn’t drinking well
These treatments work quickly and often help your child breathe more easily within hours.
FAQs
Why does my child keep getting croup?
Some kids naturally have narrower airways. If it happens more than twice a year, ask your pediatrician about an ENT referral.
What is “spasmodic” croup?
This can happen from allergies or reflux. It often appears suddenly at night and improves quickly once swelling goes down. The symptoms are the same (hoarseness, stridor, a barky cough). Treatment focuses on the underlying cause.
Does my child need to stay home from school?
Keep them home until they’re:
Fever-free for at least 24 hours
Drinking well
Breathing comfortably
Croup can sound scary, but most cases are mild and get better with home care and rest.
Keep your child calm, use steam or cool air, watch their breathing, and stay in touch with your pediatrician.
And remember: extra snuggles truly help little ones and their parents breathe easier.
