Croup is a childhood illness that is caused by the same viruses that cause the common cold and infect the upper airways.


When you breathe, air passes through the voice box (larynx) and windpipe (trachea) into the lungs. In croup, a viral infection causes inflammation and swelling of the lining of the voice box and windpipe, which become narrowed. When the airway becomes narrowed, breathing in becomes more difficult, and you can hear stridor (a harsh noise when breathing in).

Infants and toddlers between 6 months and 3 years of age are at most risk of getting croup – but children who are younger or older can also get it.

Children with croup can become seriously ill.

  • If your child has croup, they’ll probably have the symptoms of a cold for a few days, then develop a seal-like barky cough, hoarseness and noisy breathing.
  • Croup usually lasts for 5–6 days and is more common in colder weather.

The viruses that cause croup are contagious and spread when people cough or sneeze, but not every child that gets the virus will get croup, they may just have symptoms of a cold.


There are 2 types of croup: viral and spasmodic.

Viral croup

  • This begins with a cold that develops into a barky cough.
  • The child’s airway will swell, making breathing noisy and more difficult.
  • Your child may have a temperature as high as 40°C.

The greatest danger is if your child’s windpipe swells so much that they cannot breathe.

Spasmodic croup

This type of croup causes spasms that occur during the night and early morning.

  • Epiglottitis
    This is a form of croup caused by Haemophilus influenzae (Hib). It is now rare due to immunisation, but can be very serious. It may look similar to croup, but the child may look unwell and feverish.
    Your child will wake up, gasping for breath, within a few hours of going to bed.
  • During the spasms, you’ll hear hoarseness and a barky cough.
  • You might also hear a rasping noise (called ‘stridor’) when your child breathes in.

The spasms usually don’t occur during the day – and your child may seem better in their breathing and hoarseness during the day as well.


When croup is serious

Take your child to the nearest emergency department or call 111 immediately if:

  • they seem to be struggling to breathe (worse than the noisy breathing)
  • they appear extremely anxious or frightened, or look blue
  • they’re dribbling and cannot swallow
  • they cannot speak
  • their chest sinks in when trying to breathe in
  • they make a whistling or crowing sound while breathing in.

Self care

  • If your child is upset, cuddle them in your lap and try to keep them calm (reading them a story might help). If they’re upset, it can make their breathing worse.
  • If they have a sore throat, give them a cool drink to sip on – this can help soothe the throat.
  • You can give your child paracetamol if they’re in pain or are miserable with fever. Make sure to follow the dosage instructions on the package – taking more than the recommended dose is dangerous.

Keep your child calm and don’t panic. If your child has serious croup and needs to go to hospital, it is safest to go by ambulance.

Call Healthline 0800 611 116 if you are unsure what you should do.

Note: We no longer recommend using steam for croup – there is no evidence it actually helps, and in some cases children have been badly burned by the hot water.


How croup spreads

  • Croup is contagious (catching) for 4–6 days, until the fever settles.
  • It spreads through the air when people with croup sneeze or cough.

Make sure your child is fully vaccinated. The diphtheria and Haemophilus influenza type b (Hib) vaccines, that are part of the childhood immunisation schedule, offer protection from some of the rarest but most dangerous forms of croup.

Your child can return to day care or school after the fever is gone and they’re feeling better.

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