What is severe asthma?

Severe asthma is much less common than other types of asthma, affecting around 4% of people with asthma

Someone who is diagnosed with ‘severe asthma’ has a specific type of asthma which doesn’t get better with the usual medicines. Even if someone takes those medicines as prescribed a different approach is needed to control symptoms and reduce frequent asthma attacks. Other causes and triggers for the symptoms have also been ruled out as much as possible.

About 200,000 adults and children in the UK are diagnosed with severe asthma. If your GP or asthma nurse suspects you may have severe asthma they may refer you to an asthma specialist for a different kind of assessment, support and treatment. Unfortunately it’s not always easy to get this level of asthma care so you may have to continue to manage your condition through your GP or asthma nurse.

Why do people get severe asthma?

“We don’t understand yet why some people get asthma and some people get severe asthma,” says Dr Andy. “We know that each individual with asthma can have different triggers and a different chemical reaction in their airways.

“That’s why Asthma UK is supporting lots of research looking into what goes on in the body to cause severe asthma and make it so much harder to control with the usual asthma medicines.”

What causes severe asthma?

A few of the current theories are:

  • Some people’s airways may be too inflamed for the usual medicines to work well enough
  • Some people’s inflammation could be caused by chemicals that aren’t blocked or controlled by current medicines and we don’t have the right medicines to control all the chemicals that cause the inflammation
  • In some people, asthma symptoms are not caused by high levels of allergy-related cells and chemicals so the usual medicines to tackle these allergic causes don’t work.

The difference between severe asthma and difficult to control asthma

You might hear your asthma labelled as ‘difficult to control’. About 17% of people in the UK have difficult to control asthma. In comparison, severe asthma is rare – only 200,000 people are suspected to have it in the UK, and the number of people with a diagnosis is even lower. 

If you have difficult to control asthma, you should be able to work with your GP or asthma nurse to find a combination of asthma medicines that work. You might need to see an asthma specialist to work out why your asthma is difficult to control, and this may include a psychological assessment.

By contrast, normal asthma medicines don’t help with severe asthma. You'll usually need special ‘add on’ treatments.

You have difficult to control asthma if:  

  • you have asthma symptoms that won’t go away, even though you’re taking your asthma medicines
  • You end up taking oral steroids three or more times a year
  • You find yourself needing your reliever inhaler three or more times a week – one of the warning signs of an asthma attack 
  • You have frequent asthma attacks

Trying to find out which type of asthma you have can be frustrating, but once you know, you can work together with you GP or asthma nurse to find the combination of treatments that works best for you.

Who gets severe asthma?

You can develop severe asthma at any age. Your asthma can change to become severe over time, or it can be triggered more suddenly by certain factors such as pneumonia or hormonal changes. Most people who are diagnosed with severe asthma already have an asthma diagnosis. Some people are diagnosed right away with severe asthma, but it’s likely that they had asthma for some time before without it being officially diagnosed as severe.

“I was diagnosed with asthma at 35, but my GP said I’ve probably always had it. I spent a lot of time in hospital with chest infections and croup as a child. In the lead-up to my severe asthma diagnosis, aged 40, I had pneumonia and started getting a lot of infections. My asthma changed and I could barely walk or move.” – Kate Harris, 47

What is it like to have severe asthma?

It’s impossible to pinpoint exactly what it’s like to have severe asthma because the condition is unpredictable and different for everyone. The symptoms, triggers, responses to medicines, energy levels and impact on daily life are unique to each individual, plus they can change over time.

Here are a few experiences people with severe asthma have shared with us:

“I have symptoms all the time, and it stops me doing a lot of things. I can’t go out for a walk during pollen season, and often I can’t do even gentle exercise. I don’t do much socialising.” – Sean Michael, 44

“I’ve withdrawn from many things as keeping as healthy as possible takes time, energy and all of my strength. I’m usually asleep by 9.30pm to cope. My meds help to some degree but exercise has definitely improved my health.” – Kate Harris, 47

“Over the course of a few years I went from rock climbing, mountain biking, marathon running and teaching kids dance to being unable to walk upstairs. On bad days I couldn’t walk the 18 steps from my bed to my bathroom. I also found talking difficult. I would be breathless and try to disguise it around people and have to visit toilets to use my inhaler.” – Vickie Taylor, 27

“It took a while to find the medicines that worked with the minimum of side effects, but my current combination seems to be working – I have to use my reliever inhaler pretty regularly but I can still get to the gym about three times a week.” – Peter Naylor, 52

“Having severe asthma doesn’t stop me being active. I do a lot of aerial gymnastics so sometimes I’ll be hanging upside down in mid-air from a silk and realise I need my inhaler. I make sure it’s always on the side of the crash mat, and we have a buddy system (two people to each silk) so there’s always someone who can help me out.” – Abi Bettle, 28

You can find more stories from people with severe asthma here.

Are there special medicines for severe asthma?

Yes, there are some special medicines and treatments available. There’s also a great deal of scientific research going on into the different types of asthma with a view to finding effective treatments for everyone with severe asthma. There are currently several new treatments targeting specific sub-types of severe asthma available.

You will need to work with your healthcare professional to find a combination of medicines and doses that best help you manage your symptoms. This is usually a mix of asthma treatments at higher doses, and sometimes extra treatments that other people with asthma don’t need.

“It took about five years to find the best combination of medicines for me – I spent six or seven months on each one, so I felt I’d given it a fair go. My asthma nurse is always working to help me find a balance of medicines. I see her every eight to 12 weeks, whether or not there’s a problem.” – Abi Bettle, 28

What’s the outlook for people with severe asthma?

If you’ve been diagnosed with severe asthma, or think you have it, you may be concerned about what it means for you in the longer term.

“Because severe asthma is so unpredictable in the treatments it responds to and the course it takes, the long-term outlook is different for everyone,” says Dr Andy.

“Some people find their symptoms improve, some go through good and bad patches and some find their asthma symptoms get worse over time. There lots of treatments around for people with severe asthma and your team of healthcare professionals will work with you to find the right ones for you so you can have the best quality of life possible in the long term.”

The risk of long-term damage to your lungs

One of the possible long-term effects of severe asthma is something called ‘airway remodelling’. This is where your airways become thicker over time, so the airway itself is narrower, making it harder to breathe. This can happen as a result of frequent asthma attacks. If you have severe asthma, your risk increases because you’ll probably have asthma attacks more often.

It’s not clear what causes airway remodelling but lots of studies suggest inflammation, long-term exposure to pollutants including tobacco smoke and/or poor asthma control can play an important part.

You may have poor asthma control because it’s taking time to find the right medicines that work for you, or perhaps you’re not taking your medicines exactly as prescribed.

Whatever the reason, if you’re continually having lots of symptoms over a long period of time then there’s a risk your airways will become permanently narrowed, scarred and inflamed, which can mean your symptoms get worse.

How you can help reduce your risk of long-term lung damage

Changes to the structure of your airways can be avoided with good asthma management. While this is often easier said than done if you have severe asthma, because it can be a challenge to find the right treatment, there are still lots of things you can do to help manage your symptoms. Here are the top three things you can do:

  1. Go for regular reviews of your medicines to check how well they’re reducing your symptoms
  2. Work out which pollutants and irritants, such as dust, fumes and pollen, affect you so you can avoid them wherever possible
  3. Quit if you smoke – you can find lots of top tips here.

“I wish I’d known earlier that frequent asthma attacks result in permanent damage to your lungs and cause your condition to deteriorate. I didn’t know about airway remodelling until it had already happened. I saw hundreds of specialists during my childhood and no-one mentioned it – one suggested that I move to the beach, but didn’t say why.

“When I asked about it, I was told ‘it’s not a hard and fast rule’ and that it doesn’t happen to everyone, but it does happen, and people should be told. It’s an extremely serious condition – I want to tell people to avoid scarring to their lungs at all costs. I would have lived very differently – stayed away from stress, people who smoke, cats, and pollen, and lived a quiet life. Instead I took all those risks and just battled the symptoms with steroids.” – Sean Michael, 44

Complications of severe asthma

Long term severe asthma can sometimes lead to a chronic lung condition called COPD (chronic obstructive pulmonary disease) or ACO (asthma-COPD overlap). You can find out more about both these conditions here.

Do you think you may have severe asthma?

If you’d like to talk through your concerns with one of our friendly asthma nurse specialists, call the Asthma UK Helpline on 0300 222 5800 or message them via WhatsApp on 07378 606728 (Monday to Friday, 9am to 5pm).

You can find out more about how severe asthma is diagnosed here.

Finding a cure for severe asthma

Asthma UK is working with scientists, researchers and people with asthma to find new treatments for severe asthma, and ultimately, a cure. In our landmark Severe Asthma report, we explain how we’re working towards this goal and how it will help people to live longer and live better. Find out more about Asthma’s UK research into severe asthma here.


Last updated June 2019

Next review due June 2022