Clinical: coping with croup

03 October 2018

This viral infection is common and usually harmless, writes journalist John Windell, but a toddler’s barking cough and rasping breathing can still alarm parents.

Croup sounds like one of those childhood conditions that belongs in Victorian times, but it is still a common complaint in the 21st century. For example, the respiratory viral infection was one of the most searched-for health topics on Google in 2017: the question being ‘Why is croup worse at night?’ (Howard, 2017); and the Cardiff and Vale University Health Board (CVUHB) in Wales said it had seen a spike in cases of the condition last year.

The clinical name for croup is laryngotracheobronchitis, which reveals that it is an inflammation of the larynx, trachea and bronchi. It’s also a viral condition, usually caused by the parainfluenza and influenza viruses, and mostly affects children between the ages of six months and three years, peaking among two-year-olds (NICE, 2017). On rare occasions, babies as young as three months old, teenagers and even adults can also catch croup (NICE, 2017).

It’s difficult to know just how many young children in the UK get croup every year because the figures aren’t collected. Any cases that get as far as a GP surgery or hospital are added to the general category of respiratory illnesses, but most cases of croup are dealt with in the home and are not recorded at all. Muddying the waters further, the annual incidence of croup varies depending on the seasonal prevalence of viral infections in children. This is what CVUHB reported in October 2017 – not an actual rise in reported figures but an observed spike in cases during the autumn, a seasonal peak for the condition.

‘The viruses that cause croup are more common when temperatures drop,’ explains Gavin Dabrera, consultant in public health medicine at Public Health England. One study has suggested that the incidence of croup is about 60 per 1000 children aged one to two years (Moore and Little, 2007).

Causes of Croup

The bottom line about croup is that, for the vast majority of children who catch it, it is a routine condition. As Professor Helen Stokes-Lampard, chair of the Royal College of General Practitioners, says: ‘It’s fairly common and usually nothing to worry about.’

That said, the tell-tale signs of croup might, at least initially, appear alarming to parents of young children. ‘Children will often experience symptoms similar to the common cold, like a runny nose and raised temperature, before the infection takes hold,’ says Professor Stokes-Lampard. ‘The main things to look out for are a hoarse voice and a distinctive barking cough, which has been described as sounding similar to a seal.’

This barking cough is often accompanied by noisy and laboured breathing, and both are the result of constricted upper airways. The virus that causes croup inflames the windpipe and voice box, and this swelling means they become narrowed. Young children’s windpipes are already soft and narrow, so any inflammation will create problems. As they get older, and their airways mature and widen, croup becomes less of a concern.

While the cough may be fairly mild at the start of the infection, it will quickly get worse within a day or two. Though it might sound bad, especially during those first two or three days, it tends to clear up completely after around a week or so. During this phase, it’s important to keep an eye out for symptoms that might indicate something more serious is happening to the child. These include more troubled breathing, a pale or blue face after a coughing fit, a persistent high temperature, irritability and even delirium. If this is the case, it’s time to get help. ‘Anyone who is concerned about their child’s symptoms or notices difficulties in their breathing should seek advice from a healthcare professional,’ says Professor Stokes-Lampard.

Secondary bacterial infections that can lead to pneumonia, for example, are rare. Indeed, any complications with croup are generally few and far between, with one study showing that 1.5% to 6% of cases lead to a hospital visit (Knutson and Aring, 2004). And just one in 4500 children with croup need to be intubated to help them breathe (Worrall, 2008).

Still, vigilance is advised. ‘It is also important to make sure that other, more serious conditions are not accidentally mistaken for croup,’ says Professor Stokes-Lampard, ‘and to check that children don’t have symptoms that could be whooping cough or bronchiolitis.’

The treatment

Because croup is usually a mild and self-limiting condition, most children who contract it don’t require much in the way of treatment.

‘Croup normally disappears on its own within 48 hours, but it can be very contagious in the first stages, and parents are advised to keep their child hydrated and sitting in an upright position while waiting for the infection to pass,’ says Professor Stokes-Lampard.

Parents may also need to comfort and reassure a small child with croup who is crying persistently, as that crying will only make the symptoms worse. It increases the need for oxygen that is already in shorter supply, tires the muscles around the airways, and can create more mucus, all of which simply add to the problem. It is sometimes said that cool air can help to soothe inflamed airways, and that a quick walk around outside or even sitting in front of an open fridge for a few minutes can provide relief.

If needed, the recommended medication is simple over-the-counter liquid paracetamol, given according to the dosage guidelines on the bottle. This won’t cause any problems with a child’s breathing but will help to relieve the discomfort and reduce any fever. A suitable ibuprofen liquid will also help to ease the inflammation. In the unlikely event that the child needs to see a GP or go to hospital with croup, they will probably be treated with a steroid.

Remedies to avoid

Clinicians advise against certain other ‘treatments’ when dealing with croup. One of the most important is that because croup is caused by viruses, antibiotics will not work. They only become useful if a child develops a secondary bacterial infection. Another step that’s frowned upon is making children inhale humid, steamy air, simply because there is no evidence that it works (Moore and Little, 2007). Likewise, cough medicines are ineffective against croup and may even cause drowsiness, making steady breathing yet more difficult for the child. ‘Although they might work for a chesty cough, exposing children to steam or giving them cough mixture doesn’t actually help to relieve symptoms of croup,’ says Professor Stokes-Lampard.

The advice to community practitioners is to be aware of the symptoms of croup and to look out for the warning signs that the condition may be getting worse or could in fact be something more serious.

‘Health visitors and school nurses can also help by explaining that croup is caused by respiratory viruses,’ says Gavin Dabrera, ‘and to emphasise the importance of good hygiene practices, such as hand washing, to reduce the chance of spreading infections to others.’

Finally, as thousands of Google users asked, why is croup worse at night? Nobody knows for certain, but a plausible explanation is that levels of the body’s natural steroids drop during the small hours, meaning that the inflammation in the airways gets worse. Clinicians also say that lying down puts more pressure on the upper chest and so exacerbates the problem – hence their advice to keep children sat upright, as it makes it easier for them to breathe.


The tell-tale symptoms 

  • To begin with, a runny nose and raised temperature, like a cold 
  • Then a harsh, barking cough 
  • Breathing often becomes slightly laboured A rasping or whistling noise when breathing (known as stridor) 
  • A mild fever 

Treating the condition at home 

  • Sit children upright so that it is easier for them to breathe Keep well hydrated with cool drinks 
  • Comfort and reassure them to keep crying to a minimum 
  • Over-the-counter liquid paracetamol or ibuprofen can ease discomfort 
  • Cool air may help to soothe inflamed airways 

When to get help 

  • Breathing becomes harsher, faster and more difficult The child gets more restless and agitated Starts to look unusually pale 
  • The fever persists 
  • Difficulty swallowing 

(Harding, 2018; NICE, 2017)



NHS Choices has information on when to seek help at nhs.uk/conditions/croup

NICE updated its Clinical Knowledge Summary in 2017, which includes differential diagnoses. It can be found at bit.ly/NICE_croup

An overview of croup treatments is at bit.ly/croup_treatments


Harding M. (2018) Croup. See: patient.info/health/cough-leaflet/croup (accessed 11 September 2018).

Howard J. (2017) 10 health questions that had you Googling this year. See: edition.cnn.com/2017/12/15/health/health-trends-2017-google-explainer/index.html (accessed 11 September 2018).

Knutson D, Aring A. (2004) Viral croup. American Family Physician 169(3): 535-40.

NICE. (2017) Clinical knowledge summary: croup. See: cks.nice.org.uk/croup (accessed 11 September 2018).

Moore M, Little P. (2007) Humidified air inhalation for treating croup: a systematic review and meta-analysis. Family Practice 24(4): 295-301.

Worrall G. (2008) Croup. Canadian Family Physician 54(4): 573-4.

Image credit | Getty

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