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. 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 your symptoms.


What causes asthma?

Asthma is caused by inflammation of the small tubes, called bronchi, which carry air in and out of the lungs. If you have asthma, the bronchi will be inflamed and more sensitive than normal.

When you come into contact with something that irritates your lungs – known as a trigger – your airways become narrow, the muscles around them tighten, and there is an increase in the production of sticky mucus (phlegm).

Common asthma triggers include:

  • house dust mites

  • animal fur

  • pollen

  • cigarette smoke

  • exercise

  • viral infections

Asthma may also be triggered by substances (allergens or chemicals) inhaled while at work. Speak to your GP if you think your symptoms are worse at work and get better on holiday. The reason why some people develop asthma is not fully understood, although it is known that you are more likely to develop it if you have a family history of the condition. Asthma can develop at any age, including in young children and elderly people.

How asthma is treated?

While there is no cure for asthma, there are a number of treatments that can help control the condition.

Treatment is based on two important goals, which are:

  • relieving symptoms

  • preventing future symptoms and attacks

For most people, this will involve the occasional – or, more commonly, daily – use of medications, usually taken using an inhaler. However, identifying and avoiding possible triggers is also important.

You should have a personal asthma action plan agreed with your doctor or nurse that includes information about the medicines you need to take, how to recognise when your symptoms are getting worse, and what steps to take when they do so.

For many people, asthma is a long-term condition – particularly if it first develops in adulthood.

Asthma symptoms are usually controllable and reversible with treatment, although some people with long-lasting asthma may develop permanent narrowing of their airways and more persistent problems.

For children diagnosed with asthma, the condition may disappear or improve during the teenage years, although it can return later in life. Moderate or severe childhood asthma is more likely to persist or return later on.

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.

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.

If you think you or your child are having an asthma attack, don't ignore it. Contact your GP or asthma clinic as soon as possible, or consult and use your asthma action plan if you have one.

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)

Call 112 to seek immediate help if you or someone else has symptoms of a severe asthma attack.


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 andibuprofen, 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.


Treating asthma

Anyone with asthma should be able to lead a full and unrestricted life. The treatments are effective in most people and should enable you to keep the condition under control.


Asthma medicines are usually given by inhalers – devices that deliver medication directly into the lungs as you breathe in. This is an effective way of taking an asthma medicine as most goes straight to the lungs, with very little ending up elsewhere in the body.

Each inhaler works in a slightly different way. You should have training from your GP or nurse in how to use your device or how to help your child use theirs. This should be checked at least once a year. Some inhalers are pressurised canisters – similar to a spray deodorant or an air freshener. You press the inhaler while breathing in, so the vapour containing the medication can pass into your lungs.

Some inhalers are not pressurised canisters but contain the medication in dry powder form, usually in a capsule that is punctured when the inhaler is "primed". It is not possible to use a spacer with these inhalers and, unlike pressurised canisters, the powder must be inhaled quickly and forcefully if the medication is to reach the lungs.


Pressurised canister inhalers can work better if given through a spacer – a hollow plastic or metal container with a mouthpiece at one end and a hole for the inhaler at the other.

Children under the age of three may have a spacer attached to a face mask rather than a mouthpiece, as this can make it easier for them to breathe in the medicine.

When using a spacer, the vapour from the inhaler is released into the container, where it is held while you breathe in slowly and progressively until your lungs are full. You should then hold in your breath before relaxing so the vapour has time to settle in your lungs.

This can make the medication more effective because much more of it reaches your lungs and much less stays in your mouth or is swallowed, where it has no effect on your lungs but is more likely to cause possible unwanted effects.

Spacers are also good for reducing the risk of thrush in the mouth or throat, which can be a side effect of some inhaled asthma preventer medicines.

Spacers can also be very helpful for people who find using inhalers difficult, such as young children. As spacers also improve the distribution of medication into the lungs, their regular use is preferred in many cases – particularly for preventer medications – even in people who use inhalers well.


Reliever inhalers – usually blue – are taken to relieve asthma symptoms quickly.

The inhaler usually contains a medicine called a short-acting beta2-agonist, which works by relaxing the muscles surrounding the narrowed airways. This allows the airways to open wider, making it easier to breathe again.

Reliever inhalers do not reduce the inflammation in the airways, so they do not make asthma better in the long term – they are intended only for the relief of symptoms.

Examples of reliever medicines include salbutamol and terbutaline. They are generally safe medicines with few side effects, unless overused.

However, they should rarely, if ever, be necessary if asthma is well controlled, and anyone needing to use them three or more times a week should have their treatment reviewed.

Everyone with asthma should be given a reliever inhaler, also known simply as a "reliever".

Living with asthma - Below are some things you can do to help keep your asthma under control:

Your asthma may get better or worse at different times. There may be periods when you have asthma symptoms, but in between you may be generally well, possibly for many years. Below are some things you can do to help keep your asthma under control:

Self care

Self care is an integral part of daily life. It involves taking responsibility for your own health and wellbeing, with support from those involved in your care.

It includes what you do every day to stay fit and maintain good physical and mental health, prevent illness or accidents, and care more effectively for minor ailments and long-term conditions.

People living with long-term conditions can benefit enormously from being supported to care for themselves. They can live longer, have a better quality of life, and be more active and independent.

If your child has asthma, they should be encouraged to manage their condition as they get older so they learn about their medication and how to recognise and treat asthma attacks.

Take your medication

It's important that you or your child take any medication as prescribed, even if you start to feel better.

Taking a preventer medication every day using the correct technique will help keep asthma under control and can help prevent asthma attacks.

If you have any questions or concerns about medication you or your child are taking, or its side effects, talk to your doctor or asthma nurse.

Regular reviews

As asthma is a long-term condition, you'll be in regular contact with your healthcare team. You or your child should have checks to ensure the condition is under control and that your current treatment is still appropriate at least once a year.

A good relationship with your team means you can easily discuss your symptoms or concerns. The more the team knows, the more they can help.


Stop smoking

If you smoke and have asthma, you should stop smoking as this can significantly reduce the severity and frequency of your symptoms. Smoking can also reduce the effectiveness of asthma medication.

If you do not smoke and have asthma, try to avoid being exposed to tobacco smoke because this may trigger your symptoms.

If your child has been diagnosed with asthma, you should try to ensure that nobody smokes around them.

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.


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.


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

Read about health and fitness for more information on simple ways to exercise.


Most people with asthma can eat a normal, healthy diet. Occasionally, people with asthma may have food-based allergic triggers and will need to avoid foods such as cows' milk, eggs, fish, shellfish, yeast products, nuts, and some food colourings and preservatives. However, this is uncommon.

Search for DOCTOR if you think you might experience Asthma symptoms.