Defining severe asthma
Severe asthma is difficult to define. It is made more confusing because there are other words people use to describe it (difficult, brittle, refractory) and people use the term severe asthma in different ways.
This page contains information about:
- people with severe asthma symptoms
- people with difficult asthma
- people with severe asthma.
By defining it in this way, we hope to give people the best chance possible of reducing the impact that asthma has on their lives.
People with treatable severe asthma symptoms
Many people describe their asthma as severe, and their doctor or nurse may have told them they have 'severe asthma symptoms'. This is when people are currently experiencing, or experience from time to time, asthma symptoms that are severe and potentially life threatening if not treated. However, by identifying and minimising their triggers and with the right care and combination of medicines, most people in this group can get back to leading a normal life with few symptoms and only occasional flare ups.
All people with asthma could potentially experience severe asthma symptoms during bad patches. However, for this group the diagnosis would be asthma, not severe asthma. It is important not to assume it is normal to have these symptoms and to seek medical advice when asthma symptoms get worse. With effective treatment the person can resume a good quality of life with minimal symptoms.
People with difficult asthma
Some people, despite being prescribed high levels of asthma medicines, still experience constant severe asthma symptoms and life-threatening attacks. Their asthma is not under control for a variety of reasons which can include:
- Not getting the right level of support from health professionals. This may be because they are not accessing care when they need it.
- Use of medicines: people may not understand what their medicines are for and how to take them, or they may not be taking their medicines as prescribed.
- Barriers to healthcare: some people don't have access to effective healthcare or medicines due to financial, language, cultural or social barriers.
- Triggers: some people are unable, unwilling or unaware of the need to avoid persistent exposure to triggers such as cigarette smoke or exposure to workplace substances.
- Other underlying health conditions that have not been identified and which may make their asthma symptoms worse.
- Some people may be mis-diagnosed with asthma and asthma medicines will not help their symptoms.
These are the people who have 'difficult asthma'.
People with severe asthma
A small proportion of people (about 5% of people with asthma) are unable to get good control of their asthma despite using high levels of asthma medicines. This is described as therapy resistance. Many people in this group have difficulty breathing almost all of the time, as well as frequent serious, life-threatening asthma attacks needing hospital admissions.
They will have been through a process to exclude other diagnoses, have had any other existing conditions treated, have had trigger factors removed (if possible) and adherence to their medicines checked. All of this process will have been undertaken by a multi-disciplinary team in an asthma clinic. They are then given the diagnosis of 'severe asthma'.
Asthma UK's definition of severe asthma
Despite international clinical research and much debate amongst health professionals, the definition of severe asthma is still not universally agreed. Asthma UK includes the following as people with severe asthma:
- People (including children) with therapy resistant severe asthma. These are people who are unable to reduce their asthma symptoms and have frequent worsening of asthma symptoms and asthma attacks, despite taking multiple asthma medicines.
- People (including children) who are not therapy resistant but who have poorly managed difficult asthma.
Resources you might find useful