This page has information on croup in children, including how to recognise it and what to do if your child has croup.

If you have a specific question, click on the link below. Otherwise read on for a review of this common childhood condition.


What is croup?

It is an infection involving the larynx (the voice box), the trachea, (wind-pipe) and the bronchus (air tube) - so it is also known as laryngo-tracheo-bronchitis. The infection causes the lining of the airways (larynx, trachea and bronchus) to become swollen and this narrows the airway. This narrowing causes obstruction to airflow and this obstruction causes the symptoms of croup.

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What causes the infection?

The infection is usually caused by a virus - the most common one is Parainfluenzae type 3 virus. There are some infections caused by bacteria that can look similar, but they are called other names (epiglottitis, tracheitis).

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What are the symptoms of croup?

It starts off like many viral infections with symptoms of a cold for a couple of days - so:

  • runny nose
  • fever
  • being off color

Gradually over a couple of days, these symptoms appear:

  • voice becomes hoarse
  • barking cough ( a bit like a seal)
  • Finally, the obstruction to the airway (because it's swollen and narrow) causes a whistling noise when breathing in - this is called stridor.
  • Depending on the level of obstruction to the airflow (which depends on the amount of swelling of the lining and the diameter of the airway to begin with) there may be other signs of respiratory distress, such as working hard to breathe (for example, ribs becoming prominent with each breath)

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What is the treatment of croup?

  • As it is caused by a viral infection, there is no specific treatment for the infection. General measures like keeping fluids up and giving Paracetamol / Acetaminophen or Ibuprofen will often be enough - read more.
  • When stridor occurs or there is increased work of breathing, there are other medications that can be given. Most commonly, we give a steroid called dexamethasone by mouth or intramuscular injection (just one dose is enough). Alternatively, a steroid called budesonide can be given by a nebulizer (again just one dose is needed). These steroids which mimic the body's natural steroids, act to calm the inflammation in the airway and reduce the swelling of the lining of the airway, thereby reducing the obstruction to airflow.
  • If the obstruction is severe, there are other treatments, like nebulized epinephrine (adrenaline) that can be given to provide relief.

If the condition was thought to be epiglottitis or tracheitis rather than croup, intravenous antibiotics would be necessary. If your child exhibits any of the serious signs in the list below, see your doctor - go there now.

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Is this infection dangerous?

In most cases, it isn't dangerous and most children will need no more than a dose of steroid like dexamethasone or budesonide. However, the obstruction to the airway can be severe enough to compromise air getting to the lungs and in cases like these, hospital admission and artificial ventilation are necessary.

Also, the bacterial infections such as epiglottitis and tracheitis have similar symptoms and these require hospital admission and artificial ventilation. If your child has any serious symptoms, then get urgent medical attention - to view serious signs, click here.

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How long does croup last?

Like most viruses, symptoms get worse for a few days, usually reach a peak about day 3 or 4 and then improve over a few days so the whole episode lasts 7 - 10 days. Children often develop stridor on about day 3 or 4, which is often the worst part of the infection.

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Why do my child's symptoms get worse at night?

Many respiratory illnesses seem to get worse at night. It's not entirely clear why that happens but children with croup may have stridor one night and then be quite happy during the next day only to develop stridor again the next night. Don't panic - that's normal.

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What can I do at home to ease my child's distress?

The most important thing is to keep calm and to try and calm your child. Crying only makes breathing more difficult.

Although studies have not shown that humidified air works conclusively, some parents find going into the bathroom, turning on the hot taps to make a hot, steamy environment can calm their child. However, be careful not to burn or scald your child with the steam!!

Remember, if you are worried about your child's breathing, get medical attention.

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What are the signs that I need to seek medical attention for my child with croup?

  • working hard to breathe - ribs or collar bones becoming prominent with each breath
  • blue color
  • very distressed or sick looking child
  • soft voice rather than hoarse voice (could be epiglottitis)
  • your child is drooling and unable to swallow (could be epiglottitis or tracheitis)
  • your child has to sit forward to be comfortable (this means she is protecting her airway)

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Johnson D. Clinical Evidence, BMJ. 2004


To go to the top of the Croup page, click here

To go to the Breathing difficulty page, click here

To return to the Home page, click here

Last reviewed 5 June 2011

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Dr Maud MD

Dr Maud MD (MBChB, FRACP, FRCPCH), a specialist pediatrician, provides health information and medical advice for parents of babies and toddlers. Read more about Dr Maud.

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