Croup is a viral illness in babies and young children that causes a narrowing of the upper airways, often leading to a 'barking' cough (like a seal), hoarse voice and raspy breath.

Croup causes inflammation (swelling) of the voice box (larynx) and windpipe (trachea). The inflammation means the lining swells and more mucus is produced, causing a narrowing in the windpipe. As the voice box and windpipe becomes inflamed, a harsh cough develops, with hoarseness, difficulty breathing and there may be a raspy noise when breathing in (known as 'stridor'). 


When to seek medical advice

Mild cases of croup can be managed at home but more severe cases of croup will need medication from the doctor. Because croup affects the airways, it can sometimes cause serious problems in children that requires urgent medical attention.

Call an ambulance 111 for emergency help if:

  • your child has blue or dusky coloured lips (may occur after a coughing spell)
  • your child is not breathing continuously
  • your child is having extreme difficulty breathing
  • your child seems delirious or drowsy.

See a doctor urgently if your child has any of the following symptoms:

  • starts dribbling or cannot swallow
  • cannot bend their neck forward
  • is not having enough fluid
  • makes a high pitched noise or grunt when breathing in
  • has a high temperature
  • develops earache
  • is having difficulty breathing
  • or you are concerned that your child is getting worse.

For further information and support talk to your doctor or practice nurse. You can also phone Healthline on 0800 611 116 for advice.

Who gets croup?

Babies and children 6 months to 3 years are at most risk of getting croup, but children who are younger or older can also get it. As children grow, their windpipe strengthens, lessening their chance of getting croup. It is common in the autumn and spring. 

Croup is usually caused by viruses. If your child has repeated occurrences of croup (more than 1 per year), or is under the age of 6 months or over the age of 6 years and gets croup, you should contact your doctor. Your doctor may arrange further investigation or refer you to a specialist to see if there is another cause.

What are the symptoms of croup?

Croup often starts like a common cold with slight fever, red eyes, sore throat and runny nose.

  • After a few days other symptoms develop including a barking, seal-like cough and raspy noise when they breathe in (stridor).
  • Symptoms are almost always worse at night and crying generally makes the barking cough and noisy breathing worse.
  • Croup is usually worse on the 2nd or 3rd night and can last up to a week, though the cough can last longer. As the child gets better, the cough will usually become looser.
  • Croup is contagious for about 4 to 6 days, and is spread by droplets in the air from coughs and sneezes.

Some children can have a form of croup which comes on quickly, often at night, but also resolves after about an hour or so. These children may be more likely to already have asthma or to develop asthma.

How is croup treated?

The treatment of croup depends on how severe the illness is. Because croup is caused by a virus, mild cases will usually clear up on its own. You can use simple, self care measures such as those listed in the table below to keep your child comfortable. Moderate to severe cases need observation in hospital, often overnight.

Simple measures to keep your child comfortable

Keep your child calm and comfortable Try to ensure you child is kept calm and comfortable. Children are often more comfortable in the upright position. Sit toddlers and small children up with pillows. Babies may rest more comfortably in their car seat or stroller in the upright position.
Stay with your child when coughing Croup can be frightening for the parent and the child. Stay with your child all the time when they are coughing. Handle him or her gently, and talk quietly and firmly. The symptoms of croup will be worse if the child is upset and feels that you are not in control.
Keep your child hydrated Encourage your child to drink small sips of fluids regularly, to help soothe their throat and keep them hydrated.

What not to do

  • Don't use steam.
    • Previously, steam was thought to be useful in treating croup, but this is no longer regarded as a suitable treatment, nor is there any real evidence to prove it is effective. 
    • It is also seen as dangerous for the child because of the possibility of burns or scalding. Therefore do not use steam for your child's croup.
  • Do not put anything in your child's mouth to look at the throat. This may make symptoms worse.

What medications are used to treat croup?

  • Paracetamol can be given if your child has a fever or a sore throat.
  • Do not give your child cough medicines. These will dry the mucus, making the airways even smaller.
  • Sometimes steroids (prednisolone) taken by mouth are given for croup. The steroids help reduce the swelling in the airways and this will make breathing easier.
  • If the croup is very severe, your child may be given nebulised adrenaline which reduces the airway swelling and makes breathing easier.  
  • Antibiotics are not used to treat croup unless your child develops a bacterial infection as well. This can be diagnosed by your doctor.    

Learn more

Croup KidsHealth NZ
Croup Asthma + Respiratory Foundation NZ

Credits: Health Navigator Editorial Team.