Diagnosing asthma

Find out why it’s important to get a diagnosis so you can start treatment for asthma, how asthma is diagnosed, and how you can take positive steps to stay symptom free after a diagnosis.

Could it be asthma?

Common symptoms of asthma are:

  • coughing
  • wheezing
  • tightness in the chest
  • feeling short of breath. 

Not everyone with asthma will get all of these. For example, not everyone wheezes. But if you’re experiencing one or more of these symptoms, make an appointment with your GP.

Most people with well-managed asthma only have symptoms now and then. But some people have symptoms a lot of the time, particularly the small percentage (about five percent) of people with severe asthma.

A key thing with asthma is that symptoms come and go - you may not have them all the time.

Why it’s important to see your GP to confirm a diagnosis 

If you’ve noticed asthma-like symptoms, don’t ignore them. Make an appointment with your GP or an asthma nurse as soon as you can.  

The quicker you get diagnosed, the quicker you can get the right medicines to help you deal with your symptoms.

Asthma is a long-term condition that needs regular preventer treatment. If it’s not treated, it could lead to an asthma attack which can be life-threatening.

How to get a diagnosis

The first thing to do is book an appointment. Your GP or an asthma nurse can help confirm or rule out a diagnosis of asthma.

They can do this by:

  • talking about your symptoms, what sets them off, and when you get them
  • asking if anyone else in the family has asthma
  • finding out if you, or anyone in your family, have other allergies, like hay fever
  • testing how your lungs are working
  • listening to your chest for any sounds of wheezing
  • prescribing asthma treatments to see if they make a difference
  • considering any other symptoms that might suggest something else.

Asthma tests 

Alongside a full clinical assessment by your GP, you’ll need some asthma tests to confirm or rule out asthma. Your GP can see how your lungs are working with tests like peak flow, spirometry, and FeNo (fractional exhaled nitric oxide).

Your GP can usually perform these tests during the appointment, and you can see the results straight away. But you may need to do tests again on another day before your GP can confirm you have asthma.  

You may be given a peak flow meter to use at home for a couple of weeks. This is so you can record your own peak flow scores in a diary.

When you take it back to your appointment, your GP or asthma nurse will be able to see a pattern of scores that could suggest asthma.  

Trying out asthma treatments 

Your GP or asthma nurse may prescribe asthma treatments to see if they help. This is sometimes called a ‘trial of treatment.’

If your symptoms start to get better, it suggests you could have asthma.

If the results show it's unlikely you have asthma, your GP may need to investigate other possible causes for your symptoms.

“Unless you're unwell with symptoms your GP may wait for test results before prescribing any treatments. This is to make sure you get the right medicines for you and that you're not taking medicines unnecessarily,” says Dr Andy Whittamore, Asthma + Lung UK’s in-house GP.

“If your GP does recommend a trial of treatment, they will still need to arrange tests to confirm asthma at a later date.”

Diagnosis can take time 

Asthma can be complex and take time to diagnose. This is because everyone’s asthma is different and symptoms come and go. Some symptoms, like coughing and feeling breathless, are common symptoms for other conditions too.

Your GP may suspect asthma, but want to do more tests or try out treatments. This can all take a bit longer. So, unfortunately, you probably won’t get a confirmed diagnosis from just one appointment.

Getting a diagnosis for a child is different to getting a diagnosis for an adult and can take longer, particularly if your child is under five.

If your GP or asthma nurse thinks you may have severe asthma, you may need to be referred to a respiratory specialist for extra support and more specialist tests.  

Preparing for your GP appointment

A little bit of preparation can help you to get the most of your first GP appointment. It may even speed up the process so you can get diagnosed more quickly.

Have answers at the ready 

Think about your family history.

  • Does anyone in your family have asthma?
  • Does anyone in your family have allergies?
  • Do you have any allergies, including eczema or hay fever?

Your answers to these questions could help your GP work out if asthma is more likely.

Keep a diary of your symptoms 

Note down how often and when you have symptoms. For example, are your symptoms worse at night, early in the morning, or when you’re at work?

You could also make a note of what you think sets them off. Things that set off your asthma symptoms are called triggers. Common asthma triggers include dust mites, cigarette smoke, and exercise.

Keeping a diary or a chart of your symptoms and triggers can help your GP or asthma nurse see the pattern of your symptoms. Seeing how your symptoms are over time helps your GP to know if asthma is more likely.

Film symptoms on your phone 

Asthma can come and go, so you could have no symptoms when you go and see your GP.

Try filming yourself on your phone - or ask someone else to – when you’re having symptoms. Then you can show the GP or asthma nurse exactly what it was like, without having to try and describe it with words.

But don’t delay getting help if symptoms are getting worse though!

Jot down your questions

You may have lots you want to ask your GP or asthma nurse. It can be easy to forget what it was you wanted to know. Writing down questions as you think of them can help. Then you can just take your list of questions along with you to the appointment.

After your asthma diagnosis

The good news is there are lots of effective medicines available to help manage your symptoms. With the right treatment plan and good support from your GP you could stay symptom free.

Here are some things you can do straight away to get off to a good start:

Use an asthma action plan 

An asthma action plan is a simple tool to help you manage your asthma well. You fill it in with your GP or asthma nurse.

It tells you exactly how to manage your asthma every day and what to do if symptoms get worse. Evidence suggests that using one means you’re less likely to end up in hospital with an asthma attack.

Once you've got your own, personalised, asthma action plan, take it along to all your appointments to make sure it’s always up to date.

Know how to use your inhaler 

Using an asthma inhaler can be tricky to get right even if you’ve been using one for some time. Make sure you start using yours in the best way from the beginning. Some inhalers (metered dose inhalers) are best used with a spacer.

Your GP should show you how to use your inhaler and spacer in the right way, but you can also ask the pharmacist to show you when you pick up your prescription.

We have some inhaler videos too which you can watch at home.

Go to all your asthma check-ups

When you’re first diagnosed, you may need to see your GP or asthma nurse a few times to check how well your treatment is working. You can also talk about how you’re coping with your asthma.

Once you’re on top of your symptoms and in a good routine with your medicines, you won’t need appointments so often. But you should still go for an asthma review at least once a year.

Find out more about asthma reviews and when you need to see your GP or asthma nurse about your asthma at other times.

If you smoke, get support to quit 

Giving up smoking lowers your risk of asthma symptoms and attacks. It’s one of the best things you can do to help your asthma.

There’s lots of support to help you quit.

More support

We have expert advice on how to manage your asthma well and what to do if you have an asthma attack.

We also have lots of tips on living with asthma, from doing sports and going on holiday, to studying with asthma and having relationships.

Explore our health advice web pages and download our resources. The more you know about your asthma, the better you’ll be able to work with your GP or asthma nurse to manage it well.

Get support

Call our Helpline for support with your condition. Get advice on your medicines, symptoms or travelling with a lung condition, or just call us to say hello.

Did you find this information useful?

We use your comments to improve our information. We cannot reply to comments left on this form. If you have health concerns or need clinical advice, call our helpline on 0300 222 5800 between 9am and 5pm on a weekday or email them.

Page last reviewed:
Next review due: