Testing for asthma

If you want to know if your child has asthma, but you’re confused by the process and tests, this will clear it up

There are several different tests for asthma, but they’re not exact, and working out if your child has asthma can be like piecing together a jigsaw puzzle.

Parents tell us they find the process frustrating and sometimes upsetting because it can be slow and uncertain. Especially if your child is under five and they can’t do the tests.

Your doctor/nurse will try different things, which are explained below. Together they’ll help you find out whether your child does or doesn’t have asthma.

Monitoring symptoms

If your child doesn’t have symptoms that often – for example, only when they have a cold – your doctor may suggest a 'watch and wait' approach. This allows your GP to see if symptoms come back, and if they follow any pattern.

Waiting might be a worry, but they’ll often prescribe a reliever inhaler (usually blue) for your child to take when they get bad symptoms. It quickly opens up their airways, so they can breathe more easily. Learn how to give your child their reliever inhaler.

Eventually, if your child does get diagnosed with asthma, they will be on other treatment as well as the reliever.

Tell your doctor if your child’s symptoms change

Noting and reporting changes to the doctor will help them piece the puzzle together. Get tips on tracking your child’s symptoms.

Trying a preventer inhaler or other medicines

If your doctor thinks it’s likely your child has asthma, they might give them a preventer inhaler, to see if it improves their symptoms. Reasons for a preventer inhaler include:

  • your child getting a lot of symptoms
  • your child or close family members having eczema or hay fever.

Read a fuller list of what makes asthma more likely

Your doctor might call this a ‘trial of treatment’. This is because asthma is caused by inflammation in a child’s airways and the preventer inhaler works by calming down that inflammation. If the preventer medicines work, it suggests your child’s airways were inflamed. It’s another piece in the puzzle.

Things you can do to help a ‘trial of treatment’:

  • make sure your child is taking the medicine exactly as the doctor prescribed, so they can properly check whether they work
  • learn how to use your child’s inhaler and spacer – our videos will help
  • take note of any changes in your child’s symptoms, and tell the doctor when you see them. 

If you’re worried about your child taking medicines before getting a diagnosis, you’ll be reassured to know that preventer inhalers simply contain a steroid that your body releases anyway, in a very small dose. Essentially, the inhaler is just topping it up and sending the medicine straight to the airways where it’s needed. Find out more about how preventer inhalers work.

“When Beau was two and a half, we needed to use his blue reliever more than three times a week. The doctor told me it was a sign that his symptoms weren’t under control, so they gave him the brown preventer inhaler and that brought the symptoms under control.”
Anna Bonnett, mum to two boys with asthma

Stopping the preventer inhaler or other medicines

After they’ve tested them for eight weeks your doctor may take your child off the medicines. This might be because:

  • they haven’t helped your child’s symptoms. Then your doctor will start look at causes other than asthma.
  • they have helped. In this case your doctor wants to double check if the symptoms will come back without the medicines.

If the symptoms come back, it's likely your child has suspected asthma and that the medicines were helping to control it.

Your GP will probably recommend your child keeps taking medicines and you keep monitoring their symptoms, until they’re old enough to do asthma tests.

If you see a change in symptoms:

Keep a note and tell your doctor when you go back. If they get a lot worse, and you’re concerned about your child, get an urgent appointment.  

Medical asthma tests

This step is for children whose lungs are big enough and who can follow instructions – because doing the tests can be tricky. This is usually when they’re around five or over.

There are three main tests:

  • Peak flow – your child will blow into a small plastic tube called a peak flow meter, to measure how fast they can breathe out.
  • Spirometry – your child will breathe into a mouthpiece as fast as and for as long as they can, to measure how well their lungs are working.
  • Fractional Exhaled Nitric Oxide test (FeNO) – your child will breathe out a long steady breathe into a FeNo machine, which measures inflammation in airways.

Keeping your child well through the process

Even though asthma is hard to diagnose, it might help to know that children with ‘suspected asthma’ usually still get the medicines they need to stay well.

It can feel frustrating waiting for the diagnosis process to finish. But you really can help your doctor make the next decision by telling them as much as you can about your child’s symptoms. Whether they stay the same, ease off or get worse, being able to tell your doctor will make sure you get the right medicines for your child.

Take control by tracking your child’s symptoms


Last updated July 2018

Next review due July 2021

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