How is severe asthma diagnosed?

It can take time to get a severe asthma diagnosis

It can take time to get a severe asthma diagnosis

Why can severe asthma be so difficult to diagnose? 

The signs of severe asthma

Who will you see at the severe asthma clinic? 

What happens at your first appointment? 

What tests will you need to have? 

What happens next? 

Eosinophilic asthma 

Finding the right treatments for your severe asthma 

It can take time to get a severe asthma diagnosis

Just as there’s no one-off test to diagnose asthma instantly, there’s no single test to find out if the type of asthma you have is severe asthma. This means it can take time to get a diagnosis. The process and length of time will vary from person to person.

Why can severe asthma be so difficult to diagnose?

You can be diagnosed with severe asthma if your asthma fails to respond to the usual asthma medicines. There is not one test that can tell you if you have severe asthma. There are also different types of severe asthma that need different treatments. All this makes it difficult to diagnose severe asthma.

Usually a diagnosis involves different steps, including:

  • Trying a range of asthma medicines at a higher dose, or a different combination to see if they can manage your symptoms
  • Checking other causes for your symptoms, and ruling them out before a diagnosis of severe asthma can be made
  • Conducting further tests such as scans and blood tests to diagnose which kind of severe asthma you have. There are different types of severe asthma, caused by different chemical reactions in the body. These are known as sub-types and include neutrophilic and eosinophilic asthma. Depending on these results you may be suitable for specialist treatments for your severe asthma.

What are the signs that mean you may have severe asthma?

If you’ve been diagnosed with asthma and you’re taking all the usual asthma treatments as prescribed, but your symptoms haven’t improved sufficiently, your GP or asthma nurse will look for signs, including:

  • If you are needing your reliever inhaler three or more times per week
  • If you need steroid tablets two or more times in a year to manage a flare-up of your asthma 
  • If you need steroid tablets every day to help control asthma symptoms
  • What your pattern of asthma symptoms and asthma attacks is like: which symptoms you have, how often you have them, when they happen and what triggers them, what relieves the symptoms and how long for
  • What treatment you’ve needed for your asthma attacks including steroids, nebulisers, A&E or hospital stays
  • How your asthma symptoms impact on your life – for example, if you’re waking at night due to your asthma, needing time off work or school, or you’re unable to take part in exercise and activity
  • What preventer medicines you’re currently taking, or have tried previously, how long you tried them for and whether they made a difference to your asthma or caused side effects.

If your GP can see that you’re taking your asthma medicines as prescribed and they’re not controlling your symptoms, they can send you to a specialist asthma clinic for a consultation. It may take some time before you get an appointment, so you’ll still have to manage your condition through your GP until then.

Who will you see at the specialist asthma clinic?

If you’re referred for a specialist appointment, it will depend on the set-up at the clinic or centre and your own individual needs as to which healthcare professionals you will see. Your support team may include:

  • A severe asthma specialist
  • An asthma nurse specialist
  • A physiotherapist
  • A clinical psychologist
  • A physiologist
  • A pharmacist
  • A dietician and/or an allergist.

If you smoke, you may have the chance to see a smoking cessation adviser. If your asthma means you can’t work, you may be able to talk to someone about benefits.

What happens at your first appointment at the specialist asthma clinic?

The aim of your first appointment is to get the ball rolling for you and your healthcare professional to work out if you have severe asthma. You’ll probably need to answer questions you’ve answered before with your GP. If you feel confused or frustrated that you’re going over the same things again, try to remember that your new clinic needs to gather a complete picture to fully understand your individual needs.

Your asthma consultant will need to know about you − your medical history and your lifestyle. They’ll also need to know all about your asthma, including a list of the medicines you’re taking, the doses and how you’re taking them, how your asthma’s been and what kind of things usually trigger it. This is your chance to explain what impact asthma is having on your life and on your family.

The more open and honest you can be, the better chance you’ll have of getting the right diagnosis, support and treatments. So tell your healthcare professional if, for example, you’re struggling to take your medicines as prescribed or you’re getting unpleasant side effects from your current medicines.

You can find out more about preparing for this first appointment and follow-up appointments here.

What tests will you need to have?

You’ve probably already had various tests, such as blood tests and measurements of your height and weight, and some of the tests covered in detail on our tests for asthma page, including:

  • Peak flow
  • Spirometry
  • Fractional exhaled nitric oxide (FeNO)
  • Airways responsiveness. 

If your consultant thinks you may have severe asthma because of the results from these tests, they may send you for other tests to confirm this theory. These extra tests can confirm if your asthma is severe and you need severe asthma treatments to deal with it. Or these tests could also show if there are other factors involved and you need a different kind of treatment. You can find a list of these tests to confirm severe asthma – and the reasons why you might need them – here.

What will happen next?

Depending on which tests you need and when you have them, your healthcare professional may change the medicines or doses you’re taking at this first appointment, or they may wait and do that at a follow-up appointment.

If you’re taking your preventer medicines correctly but your symptoms still aren’t improving, you will probably be prescribed additional drugs in various doses and combinations to see what works for you.

You’ll be given a diagnosis of severe asthma if your healthcare professional is sure that the usual asthma medicines aren’t able to keep your symptoms under control and that there are no other causes for your symptoms that can be treated or triggers that can be avoided.

If you’re diagnosed with severe asthma, you’ll typically need treatment with a high dose of inhaled corticosteroids through an inhaler, plus a second drug such as a long-acting bronchodilator (which will usually be included in your steroid inhaler). You may also be prescribed tablets such as leukotriene receptor antagonists (montelukast) or slow-release theophylline. Occasionally some people may also need steroid tablets to help manage their asthma. 

Eosinophilic asthma

An estimated 40% of people with severe asthma are diagnosed with a specific type of severe asthma called eosinophilic asthma. This is when it looks like their asthma symptoms are caused by high numbers of a type of white blood cell called eosinophils. These white blood cells cause inflammation and will show up in a blood test or a sputum test (a test of coughed up saliva and mucus).

You might be more likely to be sent for this blood test if you have other symptoms of inflammation such as eczema, sinusitis or nasal polyps, because these cells can cause inflammation anywhere in your body and all through your whole respiratory system.

If you’re diagnosed with this type of severe asthma your asthma specialist may then be able to offer you a new type of treatment called monoclonal antibodies (also known as mAbs or biologics). These have been specially designed to control the number of eosinophil cells, which will reduce the inflammation from your nose and throat down to your lungs.

Once you start taking a mAb, you’ll be monitored to see how well it works for you. If it doesn’t work well, it will be stopped, and your healthcare professional will work out alternatives with you. 

Finding the right treatments for your severe asthma

Severe asthma is different for everyone and often so unpredictable that the combination of medicines and doses that are right for you will be very personal − and finding it may take quite some time.

During this time you may:

And don’t forget you can call our friendly asthma nurses on 0300 222 5800 or message them via WhatsApp on 07378 606 728 (Monday-Friday, 9am-5pm) to ask any questions you have about your new diagnosis.


Last updated June 2019

Next review due June 2022