Croup in Children: The Barking Cough, and When to Act
Quick answer
Croup is a common viral illness in young children that causes a distinctive barking cough, a hoarse voice and sometimes a harsh sound when breathing in. It is usually mild and settles on its own in a few days, and care is about keeping your child calm and comfortable while it passes. Croup can be frightening to hear, so the key things to know are how to keep your child calm and when their breathing means you should see a doctor or call 000. This article is general information only and is not a substitute for medical advice — if you are worried, contact your GP, call healthdirect on 1800 022 222, or in an emergency call 000.
On this page
- What is croup?
- What does a croup cough sound like?
- Why is croup worse at night?
- Is croup contagious, and for how long?
- How long does croup last?
- Can adults get croup?
- Croup vs a normal cough vs whooping cough
- Caring for your child at home
- When to see a doctor, and when to call 000
- School and childcare: when can they go back?
- FAQs
What is croup?
Croup is a viral infection that causes swelling in the voice box (larynx) and windpipe (trachea). That swelling narrows the airway, which is what gives croup its barking cough and hoarse voice. It is most common in children aged six months to five years, and tends to appear in late autumn and winter.
Most croup is mild and clears up at home in a few days. It is usually caused by the same kinds of viruses that cause a cold, most often the parainfluenza virus. Because the airway in a young child is small, even a little swelling can make breathing noisy — which can sound alarming even when croup is mild.
What does a croup cough sound like?
The croup cough is often described as a harsh, barking cough — many parents say it sounds like a seal or a small dog. Alongside the bark, your child may have a hoarse or croaky voice and a high-pitched, raspy sound when they breathe in. That breathing-in sound is called stridor.
Other common symptoms include:
- A barking cough that is usually worse at night
- A hoarse or croaky voice
- A blocked or runny nose and mild fever in the day or two before the cough starts
- A harsh, raspy sound when breathing in (stridor)
You can read more and hear what to listen for on the Royal Children's Hospital Melbourne fact sheet.
Why is croup worse at night?
Croup very often flares up in the evening and overnight. Airway swelling tends to be more noticeable when a child is lying down and tired, and being upset or crying can make the cough and the noisy breathing worse. Symptoms usually ease during the day and can return the next night, often for two or three nights in a row.
Is croup contagious, and for how long?
Yes. The viruses that cause croup spread the same way as a cold — through droplets from coughing and sneezing, and by touching contaminated hands and surfaces. A child is generally most contagious in the first few days, while they have a fever and cold symptoms. Once the fever has gone and they are well in themselves, they are much less likely to pass it on, even if a little cough lingers.
How long does croup last?
Most croup is short-lived. The barking cough and noisy breathing usually settle within three to four days, although a milder cough can linger for up to a week or two as your child recovers. Croup tends to be worst on the first two or three nights and then improves. There is no specific cure — care is about keeping your child calm and comfortable while the virus passes.
Can adults get croup?
Croup is far more common in young children because their airways are small, so even mild swelling causes the barking cough. Adults can catch the viruses that cause croup, but because their airways are larger it usually shows up as an ordinary cold or sore throat rather than croup itself.
Croup vs a normal cough vs whooping cough
The sound of the cough is the clearest guide to telling these apart.
| Croup | Normal cold cough | Whooping cough | |
|---|---|---|---|
| The sound | Harsh barking cough, like a seal; hoarse voice | Wet or dry cough, no bark | Bursts of coughing, often with a whoop on breathing in |
| Breathing | Raspy noise breathing in (stridor), worse at night | Usually normal | Can struggle to catch breath between coughing fits |
| Typical cause | Virus (often parainfluenza) | Common cold viruses | Bacteria (pertussis); vaccine-preventable |
| Typical length | A few days, cough may linger 1–2 weeks | About 1 week | Several weeks or longer |
If you are not sure which one your child has — or the cough is severe or your child seems unwell — see your GP. For more on telling childhood illnesses apart, see our guide to recognising common childhood illnesses.
Caring for your child at home
For mild croup, the most useful thing you can do is keep your child calm — being upset makes the cough and noisy breathing worse. There is no specific cure, so the goal is comfort while the illness passes:
- Stay calm and comfort them. Cuddle your child and keep them settled. Sitting them upright, for example on your lap, is often more comfortable than lying flat.
- Offer plenty of fluids. Small, frequent drinks help, especially if they have a fever or a blocked nose.
- Keep an eye on their temperature. A forehead thermometer makes it easy to check on a fever without disturbing a resting child. For what is normal at different ages, see our guides to a baby's normal temperature and bringing down a toddler's fever.
- Help them feel comfortable. If your child also has a fever, a FeverMates cooling patch can offer a cooling sensation that some children find soothing. A cooling patch is for comfort only — it does not lower a temperature.
- Pain and fever relief. Your pharmacist or GP can advise whether paracetamol is suitable for your child's age and weight to ease discomfort.
- Rest. Let your child rest and stay home while they are unwell. Avoid smoke around the home, as it can irritate the airway.
Cough medicines are not recommended for young children, and steam from hot water is no longer advised because it does not help and carries a scald risk. If your child has moderate or severe croup, a doctor may prescribe a single dose of a steroid to reduce the airway swelling.
When to see a doctor, and when to call 000
See your GP or call healthdirect on 1800 022 222 (or 13 HEALTH on 13 43 25 84 in Queensland) if:
- Your child's croup is not improving, or it lasts more than three or four days
- They have a high fever or seem generally unwell
- A baby under six months develops a barking cough
- You are unsure how unwell your child is
Call 000 straight away if your child:
- Has a harsh, raspy noise (stridor) when breathing in while resting or calm — not only when crying
- Is struggling to breathe, breathing fast, or sucking in the skin around the ribs and neck
- Looks pale or has a blue tinge around the lips
- Is very distressed, drooling, or cannot speak, cry or swallow
- Becomes very drowsy or hard to wake
School and childcare: when can they go back?
Keep your child home while they have a fever and are unwell. Once the fever has gone and they are eating, drinking and feeling like themselves again, they can usually return to childcare or school, even if a mild cough lingers. Let your centre or school know, as they may have their own guidance.
It is worth keeping a few basics on hand for childhood illnesses — a thermometer, hand sanitiser and a first aid kit. You can see the full FeverMates range in our online shop.
Frequently asked questions
What does a croup cough sound like?
A croup cough is a harsh, barking cough that many parents say sounds like a seal or a small dog. It often comes with a hoarse voice and a raspy sound when breathing in, called stridor, and is usually worse at night.
Is croup contagious, and for how long?
Yes. The viruses that cause croup spread like a cold, through coughing, sneezing and touch. A child is most contagious in the first few days while they have a fever and cold symptoms, and much less so once the fever has gone.
How long does croup last?
Most croup settles within three to four days and is usually worst on the first two or three nights. A milder cough can linger for up to a week or two while your child recovers. There is no specific treatment that speeds it up.
Why is croup worse at night?
Airway swelling tends to be more noticeable when a child is lying down and tired, and being upset can make the cough worse. Symptoms often ease during the day and return the next night, usually for two or three nights.
When should I call 000 for croup?
Call 000 if your child has a raspy noise (stridor) breathing in while calm or resting, is struggling to breathe or sucking in around the ribs, looks pale or blue around the lips, cannot speak, cry or swallow, or becomes very drowsy.
Sources
Royal Children's Hospital Melbourne — Croup; healthdirect Australia — Croup; Raising Children Network — Croup. Reviewed against Australian guidance.
This article is general information only and is not a substitute for medical advice. If you are worried about your child's breathing or health, contact your GP, call healthdirect on 1800 022 222, or in an emergency call 000.