Diagnosing asthma

Find out how asthma is diagnosed, what to do if you have symptoms, and what to do if you are diagnosed with asthma.

Could it be asthma?

The most common symptoms of asthma are:

  • coughing
  • wheezing
  • breathlessness
  • a tight chest.

Not everyone with asthma gets all of these symptoms. It’s more likely to be asthma if: 

  • you have more than one of these symptoms
  • your symptoms happen often
  • your symptoms are worse at night and early in the morning
  • your symptoms happen when you come into contact with an asthma trigger like pollen or animals, or when you have a cold or virus.

If you have asthma symptoms

Book an appointment with your GP as soon as possible. If you have asthma, it’s very important to get a diagnosis so that you can get the right medicines.

Asthma is a long-term condition that needs regular treatment. If it’s not treated, it could lead to an asthma attack which could be life-threatening. With the right treatment, most people can control their asthma well and be free of symptoms. 

We have more information about the symptoms of asthma.

Preparing for your GP appointment

It's a good idea to prepare for your appointment. This will help you get the most out of it. Preparing for your appointment can also help if you feel nervous or worried about your symptoms.

Have your answers ready

Your GP or nurse will ask you questions about your general health, symptoms, and family history, such as:

  • What are your symptoms?
  • How often do you get symptoms? 
  • Are your symptoms worse at certain times, like during the night or early in the morning? 
  • Are your symptoms better when you’re away from work? 
  • Have you noticed your symptoms getting worse when you’re near particular substances like dust, cigarette smoke, or pollen?
  • Do your symptoms get worse when you exercise or when it’s cold? Are they worse when you’re ill or stressed?
  • Do you have any allergies or allergic conditions like eczema or an itchy, runny nose (allergic rhinitis) or hay fever
  • Does anyone in your family have asthma, allergies, or an allergic condition? 
  • Do you have any other health conditions?

It can help to write down details of your symptoms and any questions you want to ask the GP or nurse, so that you do not forget to say anything. You could also take a video of your symptoms to show the GP or nurse.

It’s also a good idea to keep a symptom diary to record when your symptoms are worse. Make a note of anything that seems to set your symptoms off. These are called triggers, and can be things like dust mites, cigarette smoke, cold air and stress.

How is asthma diagnosed?

At your appointment, your GP or a nurse will:

  • consider any other symptoms that might suggest something other than asthma
  • test how your lungs are working
  • listen to your chest for any sounds of wheezing 
  • prescribe asthma treatments to see if they make a difference.

Asthma tests

Your GP or nurse can see how your lungs are working by doing tests such as:

  • peak flow, which measures how quickly you can blow air out of your lungs 
  • spirometry, which measures how much air you can breathe out in one forced breath 
  • FeNo (fractional exhaled nitric oxide), which measures how much nitric oxide is in your breath, as this can be a sign of inflamed airways.

These tests involve breathing or blowing into special devices. Your GP or nurse can usually do them during your appointment. You may have to repeat some of these tests at another appointment to help the GP or nurse confirm whether you have asthma.

Your GP or nurse may give you a peak flow meter to take readings yourself over two or more weeks. You can record your peak flow scores in our peak flow diary. When you go for your next appointment, your GP or nurse will be able to see if your pattern of scores suggest you have asthma.

Trying out asthma treatments

If your GP or nurse thinks you may have asthma, they may prescribe asthma treatments to see if they help. If your symptoms start to get better with treatment, it’s a sign you have asthma.  

If the results of your tests show it’s unlikely you have asthma, or if treatments do not help, your GP will investigate other causes for your symptoms. 

Diagnosis can take time

Asthma is different for everyone who has it, and symptoms vary over time. It also shares symptoms with other conditions. Your GP or nurse will want to do tests and try out treatments before confirming a diagnosis of asthma.

For this reason, you may not get a confirmed diagnosis in your first appointment. It’s important that the diagnosis is thorough to make sure you get the correct treatment.

Some people may be referred to a respiratory specialist for more tests before a diagnosis can be made.

Children can take longer to diagnose, especially if they are under five. We have more information on getting your child diagnosed.

What to do after your asthma diagnosis

If you are diagnosed with asthma, there are things you can do straight away to start managing it well:

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 nurse.  

It's a record of how to manage your asthma and what to do if your symptoms get worse. It helps you keep your asthma under control. Take your completed asthma action plan to your asthma reviews to make sure it’s always up to date.

Use your inhaler correctly

It’s important to make sure you’re using your inhaler correctly. For some inhalers, your GP may recommend that you also use a spacer.

Your GP should show you how to use your inhaler correctly when they prescribe it. You can also ask the pharmacist to show you when you pick up your prescription.

We have inhaler videos which you can watch to check your technique.

Go to all your asthma check-ups

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

Once you’re used to managing your asthma, you should not need to have appointments very often. You will still have an asthma review at least once a year, which you should go to even if your asthma is under control.  

If you smoke, get support to quit

If you smoke, quitting is one of the best things you can do to lower your risk of asthma symptoms and attacks.

We have advice to help you quit.

Learning how to manage your asthma

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

We also have a lot of advice on living with a lung condition, from dealing with cold weather and air pollution to planning holidays and eating healthily.

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.

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