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Croup is a condition caused by a viral infection. The virus leads to swelling of the voice box (larynx) and windpipe (trachea). This swelling makes the airway narrower, so it is harder to breathe. Children with croup develop a harsh, barking cough and may make a noisy, high-pitched sound when they breathe in (stridor).
Croup mostly affects children between six months and five years old, but it can affect older children. Some children get croup several times.
Croup can get worse quickly. If your child is having problems breathing, seek urgent medical attention.
Signs and symptoms of croup
- Croup usually begins like a normal cold, e.g. fever, runny nose and cough.
- Your child's cough will change to become harsh and barking, and might sound like a seal.
- Your child's voice may be hoarse.
- When your child breathes in, they may make a squeaky, high pitched noise, which is called stridor.
- In severe cases of croup, the skin between the child’s ribs or under their neck may suck in when they breathe, and they may struggle to breathe.
Croup often begins without warning, in the middle of the night. The symptoms are often worse at night, and are at their worst on the second or third night of the illness. The signs and symptoms of croup may last for three to four days; however, a cough may linger for up to three weeks. The stridor should not persist.
Care at home
A mild attack of croup is when your child has the harsh, barking cough but does not have stridor when they are calm and settled, and they are not struggling to breathe. No medical treatment is necessary for mild croup, or the virus that has caused it. You can usually manage mild croup at home with the following care:
- Keep your child calm, as breathing is often more difficult when upset – the more a child is distressed, the worse their symptoms can become. Try sitting quietly, reading a book, or watching TV.
- If your child has a fever and is irritable, you may give them paracetamol or ibuprofen. See our fact sheet
Pain relief for children.
- Croup often becomes worse at night. Many children will be more settled if someone stays with them.
Steam and humidifiers are no longer recommended as treatment. There is no evidence to suggest they are beneficial.
When to see a doctor
You should call an ambulance immediately if:
- your child is struggling to breathe
- your child looks very sick and becomes pale and drowsy
- your child’s lips are blue in colour
- your child starts to drool or can’t swallow.
You should see a doctor if:
- your child is under six months old and has signs and symptoms of croup
- your child's breastbone or the skin between their ribs sucks when they breathe in
- your child has stridor when at rest
- your child is very distressed or their symptoms are getting worse
- you are worried for any other reason.
If your child has mild croup that lasts for more than four days, or if stridor returns after your child has recovered from croup, take them to see a doctor.
Your doctor may prescribe steroids (e.g. prednisolone or dexamethasone) to be taken by mouth. The steroids help reduce the swelling in the airway, which will make breathing easier. Antibiotics do not work on viruses and are not given to children with croup.
If your child has severe croup, they will need to stay in hospital, where they will be closely watched.
How is croup spread?
Even though not all children get croup when infected by the virus, the virus that has caused the croup can be spread easily from person to person by coughing and sneezing. If your child has croup, you should keep them away from school and child care while they are unwell so that they don’t spread the virus that is causing the croup. Regularly washing hands thoroughly can help prevent the spread of viruses.
Key points to remember
- No treatment is necessary for mild croup, or the virus that has caused it.
- Croup usually gets better in three to four days.
- Try to calm your child, as breathing is often more difficult when your child is upset.
- Croup can get worse quickly. If your child is having problems breathing, seek urgent medical assistance.
- In a severe attack of croup, your child needs to be watched closely in a hospital.
For more information
Common questions our doctors are asked
Should I use steam to treat croup?
No. In the past, some doctors recommended exposure to mist or steam therapy, including the use of vaporisers. Research evidence now shows this to be of no benefit and it is no longer recommended.
Developed by The Royal Children's Hospital General Medicine and Respiratory and Sleep Medicine departments, and Centre for Community Child Health. We acknowledge the input of RCH consumers and carers.
Reviewed August 2020.
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