Diagnosing croup 

A GP can diagnose croup by studying your child's symptoms, particularly the sound of their cough. They may also check your child's temperature for a fever and ask whether they have recently had a cold or viral infection.

In some cases, a pulse oximetry test may be carried out. This involves clipping a sensor onto your child's earlobe or finger to find out their oxygen levels.

The test does not hurt and should not distress your child, and determines whether your child is absorbing enough oxygen into their blood.

Your GP will decide whether your child needs to be admitted to hospital or whether their croup is safe to treat at home.

You should not try to check your child's throat yourself, because it could trigger a spasm (sudden narrowing) of the airway. This could cause the airway to swell even more, making breathing even more difficult.

Ruling out other conditions

Croup can usually be diagnosed by studying your child’s symptoms, but your GP may want to rule out other conditions that can cause similar symptoms.

Other possible causes for your child’s symptoms are:

  • an abnormality of the airway, which has been present from birth
  • an abscess in the tissues in the back of the throat
  • inhaled material (something they have breathed in)
  • swelling of the deeper layers of the skin (angio-oedema)
  • epiglottitis
  • congenital lesion
  • an allergic reaction

In very rare cases, epiglottitis (inflammation of the epiglottis) or tracheitis (inflammation of the windpipe) can cause similar symptoms to croup. In these cases, however, your child will usually feel very unwell generally, rather than just having the specific symptoms of croup.

Differentiating these causes from croup may require further tests.

Further investigation

If your child is admitted to hospital with severe croup, or if treatment is unsuccessful, further investigations may be needed to examine their neck and chest area for a possible obstruction.

An X-ray may be recommended if it is thought your child may have inhaled something and it is obstructing their airway. 

Page last reviewed: 28/08/2014

Next review due: 28/08/2017