Asthma is a common long-term condition that can cause coughing, wheezing, chest tightness and breathlessness.
The severity of these symptoms varies from person to person. Asthma can be controlled well in most people most of the time, although some people may have more persistent problems.
Occasionally, asthma symptoms can get gradually or suddenly worse. This is known as an ‘asthma attack’, although doctors sometimes use the term ‘exacerbation’.
Severe attacks may require hospital treatment and can be life threatening, although this is unusual.
Read more about the symptoms of asthma and diagnosing asthma
Symptoms of asthma
The symptoms of asthma can range from mild to severe. Most people will only experience occasional symptoms, although a few people will have problems most of the time.
The main symptoms of asthma are:
- wheezing (a whistling sound when you breathe)
- shortness of breath
- a tight chest – which may feel like a band is tightening around it
- coughing
These symptoms are often worse at night and early in the morning, particularly if the condition is not well controlled. They may also develop or become worse in response to a certain trigger, such as exercise or exposure to an allergen.
Read our page on the causes of asthma for more information about potential triggers.
Causes of asthma
It’s not clear exactly what causes asthma, although it is likely to be a combination of factors.
Some of these may be genetic. However, a number of environmental factors are thought to play a role in the development of asthma. These include air pollution, chlorine in swimming pools and modern hygiene standards (known as the ‘hygiene hypothesis’).
There is currently not enough evidence to be certain whether any of these can cause asthma, although a variety of environmental irritants, such as dust, cold air and smoke, may make it worse.
Who is at risk?
Although the cause of asthma is unknown, a number of things that can increase your chances of developing the condition have been identified. These include:
- a family history of asthma or other related allergic conditions (known as atopic conditions) such as eczema, food allergy or hay fever
- having another atopic condition
- having bronchiolitis (a common childhood lung infection) as a child
- childhood exposure to tobacco smoke, particularly if your mother also smoked during pregnancy
- being born prematurely, especially if you needed a ventilator to support your breathing after birth
- having a low birth weight as a result of restricted growth within the womb
Some people may also be at risk of developing asthma through their job.
Asthma triggers
In people with asthma, the small tubes (bronchi) that carry air in and out of the lungs become inflamed and more sensitive than normal.
This means that when you come into contact with something that irritates your lungs (a trigger), your airways become narrow, the muscles around them tighten, and there is an increase in the production of sticky mucus (phlegm).
Asthma symptoms can have a range of triggers, such as:
- respiratory tract infections – particularly infections affecting the upper airways, such as colds and the flu
- allergens – including pollen, dust mites, animal fur or feathers
- airborne irritants – including cigarette smoke, chemical fumes and atmospheric pollution
- medicines – particularly the class of painkillers called non-steroidal anti-inflammatory drugs (NSAIDs), which includes aspirin and ibuprofen, and beta-blockers sometimes given for high blood pressure or some types of heart disease
- emotions – including stress or laughing
- foods containing sulphites – naturally occurring substances found in some food and drinks, such as concentrated fruit juice, jam, prawns and many processed or pre-cooked meals
- weather conditions – including a sudden change in temperature, cold air, windy days, thunderstorms, poor air quality and hot, humid days
- indoor conditions – including mould or damp, house dust mites and chemicals in carpets and flooring materials
- exercise
- food allergies – including allergies to nuts or other food items
Once you know your asthma triggers, you may be able to help control your condition by trying to avoid them.
Speak to your GP if you think you or your child may have asthma. You should also talk to your doctor or asthma nurse if you have been diagnosed with asthma and you are finding it difficult to control the symptoms.
Asthma attacks
When asthma symptoms get significantly worse, it is known as an asthma attack or ‘acute asthma exacerbation’.
Asthma attacks often develop slowly, sometimes taking a couple of days or more to become serious, although some people with asthma are prone to sudden, unexpected severe attacks. It is important to recognise attacks early and take appropriate action.
During an asthma attack, the symptoms described above may get worse and – if you’re already on treatment – your inhaler medication may not work as well as it normally does.
You might be monitoring your asthma using a device called a peak flow meter, and there may be a drop in your peak expiratory flow. Read about diagnosing asthma for more information.
Signs of a particularly severe asthma attack can include:
- your reliever inhaler (which is usually blue) is not helping symptoms as much as usual, or at all
- wheezing, coughing and chest tightness becoming severe and constant
- being too breathless to eat, speak or sleep
- breathing faster
- a rapid heartbeat
- feeling drowsy, exhausted or dizzy
- your lips or fingers turning blue (cyanosis)
Diagnosing asthma
If you have typical asthma symptoms, your GP will often be able to make a diagnosis.
They will want to know when the symptoms happen and how often, and if you have noticed anything that might trigger them.
Your GP may also ask whether you have any allergic (atopic) conditions such as eczema and hay fever, which often occur alongside asthma.
A number of tests can be carried out to confirm the diagnosis. These are described below.
In children, asthma can be difficult to diagnose because many other conditions can cause similar symptoms in infants. The tests outlined below are also not always suitable for children.
Your GP therefore may sometimes suggest that your child uses an asthma inhaler as a trial treatment. If this helps improve your child’s symptoms, it is likely they have asthma.
Spirometry
A breathing test called spirometry will often be carried out to assess how well your lungs work. This involves taking a deep breath and exhaling as fast as you can through a mouthpiece attached to a machine called a spirometer.
The spirometer takes two measurements – the volume of air you can breathe out in the first second of exhalation (the forced expiratory volume in one second, or FEV1) and the total amount of air you breathe out (the forced vital capacity or FVC).
You may be asked to breathe into the spirometer a few times to get an accurate reading.
The readings are then compared with average measurements for people your age, sex and height, which can show if your airways are obstructed.
Sometimes an initial set of measurements is taken, and you are then given a medicine to open up your airways (a reliever inhaler) to see if this improves your breathing when another reading is taken.
This is known as reversibility testing, and it can be useful in distinguishing asthma from other lung conditions, such as chronic obstructive pulmonary disease (COPD).
Peak expiratory flow test
A small hand-held device known as a peak flow meter can be used to measure how fast you can blow air out of your lungs in one breath. This is your peak expiratory flow (PEF) and the test is usually called a peak flow test.
This test requires a bit of practise to get it right, so your GP or nurse will show you how to do it and may suggest you take the best of two or three readings.
You may be given a peak flow meter to take home and a diary to record measurements of your peak flow over a period of weeks. This is because asthma is variable and your lung function may change throughout the day.
Your diary may also have a space to record your symptoms. This helps to diagnose asthma and, once diagnosed, will help you recognise when your asthma is getting worse and aid decisions about what action to take.
To help diagnose asthma that may be related to your work (occupational asthma), your GP may ask you to take measurements of your peak expiratory flow both at work and when you are away from work. Your GP may then refer you to a specialist to confirm the diagnosis.
Other tests
Some people may also need a number of more specialised tests. The tests may confirm the diagnosis of asthma or help diagnose a different condition. This will help you and your doctor to plan your treatment.
Airways responsiveness
This test is sometimes used to diagnose asthma when the diagnosis is not clear from the more simple tests discussed above. It measures how your airways react when they come into contact with a trigger.
You will be asked to breathe in a medication that deliberately irritates or constricts your airways slightly if you have asthma, causing a small decrease in your FEV1 measured using spirometry and possibly triggering mild asthma symptoms. If you do not have asthma, your airways will not respond to this stimulus.
The test often involves inhaling progressively increasing amounts of the medication at intervals, with spirometry measurement of FEV1 in between to see if it falls below a certain threshold. In some cases, however, exercise may be used as a trigger.
Testing airway inflammation
It may also be useful in some cases to carry out tests to check for inflammation in your airways. This can be done in two main ways:
- a mucus sample – the doctor may take a sample of mucus (phlegm) so it can be tested for signs of inflammation in the airways
- nitric oxide concentration – as you breathe out, the level of nitric oxide in your breath is measured using a special machine; a high level of nitric oxide can be a sign of airway inflammation
Allergy tests
Skin testing or a blood test can be used to confirm whether your asthma is associated with specific allergies, such as dust mites, pollen or foods.
Tests can also be carried out to see if you are allergic or sensitive to certain substances known to cause occupational asthma.
Living with asthma
With the right treatment and management, asthma shouldn’t restrict your daily life (including your sleep) in any way. You should work with your healthcare professionals and strive to achieve this goal.
You should also be confident about how to recognise when your asthma is getting out of control, and what to do if it does.
Sleeping
Asthma symptoms are often worse at night. This means you might wake up some nights coughing or with a tight chest.
If your child has asthma, poor sleep can affect their behaviour and concentration, as well as their ability to learn.
Effectively controlling asthma with the treatment your doctor or nurse recommends will reduce the symptoms, so you or your child should sleep better.
Read about living with insomnia for more tips on getting better sleep.
Exercise
Very occasionally, people with asthma develop symptoms only during exercise. However, usually this is a sign that your asthma could be better controlled generally.
If you or your child have asthma symptoms during or after exercise, speak to your doctor or asthma nurse. It is likely they will review your general symptoms and personal asthma plan to make sure the condition is under control.
Your doctor or asthma nurse may also advise that:
- you make sure the people you are exercising with know you have asthma
- you increase your fitness levels gradually
- you always have your reliever inhaler (usually blue) with you when you exercise
- you use your reliever inhaler immediately before you warm up
- you ensure that you always warm up and down thoroughly
- if you have symptoms while you are exercising, stop what you’re doing, take your reliever inhaler and wait until you feel better before starting again
