Asthma is a common lung condition that causes occasional breathing difficulties.
It affects people of all ages and often starts in childhood, although it can also appear for the first time in adults.
There's currently no cure for asthma, but there are simple treatments that can help keep the symptoms under control so it doesn't have a significant impact on your life.
Some people, particularly children, may eventually grow out of asthma. But for others it's a lifelong condition. Continue reading to learn more about the symptoms, causes, treatments and complications of asthma.
The main symptoms of asthma are:
The severity of the symptoms varies from person to person. They usually come and go, but for some people they're more persistent.
Asthma symptoms can sometimes get temporarily worse. This is known as an asthma attack.
Read more about the symptoms of asthma.
See your doctor if you think you or your child may have asthma.
Several conditions can cause similar symptoms, such as a chest infection or chronic obstructive pulmonary disease (COPD) , so it's important to get a proper diagnosis and correct treatment.
Your doctor will usually be able to diagnose asthma by asking about your or your child's symptoms and carrying out some simple breathing tests.
But these are often difficult to do in infants and young children, so the diagnosis may be made on the basis of symptoms and response to a trial of treatment with an inhaler.
Read more about how asthma is diagnosed.
Asthma is caused by inflammation (swelling) of the breathing tubes that carry air in and out of the lungs.
This inflammation makes the breathing tubes highly sensitive, so they temporarily become narrow. This may occur randomly, or after exposure to a trigger. The tubes may also sometimes become clogged with sticky mucus.
Common asthma triggers include:
The reason why some people develop asthma isn't fully understood, although it's known that you're more likely to develop it if you have a close relative with the condition.
Read more about the causes of asthma.
While there's currently no cure for asthma, there are a number of treatments that can help control the condition.
Most asthma treatments are taken using an inhaler, a small device that delivers a spray or powder medicine to your breathing tubes as you breathe in.
The main treatments are:
You'll usually draw up a personal action plan with your doctor or asthma nurse. This will include information about your medicines, how to monitor your condition and what to do if you have an asthma attack.
Asthma is a long-term condition for many people – particularly if it first develops in adulthood.
In children, it sometimes disappears or improves during the teenage years, although it can return later in life.
The symptoms can usually be controlled with treatment and most people will have normal and active lives, although some people with more severe asthma may have persistent problems.
Although asthma can normally be kept under control, it's still a serious condition that can cause a number of complications.
This is why it's so important to follow your treatment plan and not ignore your symptoms if they're getting worse.
Badly controlled asthma can cause issues such as:
There's also a risk of life-threatening complications, such as severe asthma attacks.
Most children and adults with asthma find they have times when their breathing becomes more difficult.
Some people with more severe asthma may have breathing problems most of the time.
The most common symptoms of asthma are:
These symptoms can have a number of causes, but they're more likely to be asthma if they:
See your doctor if you think you or your child may have asthma, or if you have asthma and you're finding it hard to control your symptoms.
Asthma symptoms can sometimes get worse for a short time – known as an asthma attack. This can happen suddenly, or gradually over a few days.
Signs of a severe asthma attack include:
If you've been diagnosed with asthma, your reliever inhaler (usually blue) may not help and your peak flow reading may be much lower than normal.
The exact cause of asthma is unknown.
People with asthma have inflamed (swollen) and "sensitive" airways that become narrow and clogged with sticky mucus in response to certain triggers.
Factors such as a genes, air pollution, chlorine in swimming pools and modern hygiene standards have been suggested as possible causes, but there's not currently enough evidence to be certain whether any of these do cause asthma.
While the cause of asthma is unknown, there are a number of things that can increase your chances of developing it. These include:
Some people may also be at risk of developing asthma through their job.
Asthma symptoms often occur in response to a trigger.
Common triggers include:
Once you know your triggers, trying to avoid them may help control your asthma symptoms.
Learn more about asthma triggers at Asthma UK: asthma triggers.
In some cases, asthma is associated with substances you may be exposed to at work. This is known as "occupational asthma".
Some of the most common causes of occupational asthma include:
You may be at an increased risk of developing occupational asthma if you are regularly exposed to substances such as these through your work.
Paint sprayers, bakers and pastry makers, nurses, chemical workers, animal handlers, welders, food processing workers and timber workers are all examples of people who may have a higher risk of being exposed to these substances.
Want to know more?
There's no single test for asthma, but it can usually be diagnosed from your symptoms and some simple breathing tests.
Your doctor will often be able to diagnose asthma. But they may refer you to a specialist if they're not sure what's causing your symptoms.
Your doctor may ask:
The tests below may be used to help confirm the diagnosis, although they aren't always practical – particularly in young children.
If your doctor feels tests aren't needed, he or she may just give you or your child an asthma inhaler to use for a short time. If this helps, it's likely you or your child have asthma.
Two simple breathing tests are sometimes used to help your doctor diagnose asthma.
A test called spirometry can help show how well your lungs and airways are working.
It involves breathing out as fast as you can through a mouthpiece attached to a machine called a spirometer.
The spirometer takes two measurements – the amount of air you breathe out in the first second and the total amount of air you can hold in your lungs.
The readings are compared with a normal measurement for someone of your age, gender and height to work out if your airways are narrow.
Sometimes the test may be repeated a few minutes after taking a puff from an asthma inhaler to see if your result improves. If your breathing tubes are narrow at the time of the test, a better result after using an inhaler means it's likely you have asthma.
A peak flow test is a simple test to measure how fast you can blow air out of your lungs in one breath.
It involves breathing out as quickly and as hard as you can into a small device called a peak flow meter.
The result is compared to what's normal for someone of your age, height and gender.
You may be given a peak flow meter to take home to record your peak flow over a period of weeks, particularly if asthma is suspected but your peak flow and spirometry are normal when measured, as asthma symptoms and peak flow can vary over time.
To help diagnose work-related asthma , you may be asked to measure your peak flow at work and away from work.
Occasionally, you may be referred to a specialist doctor for further tests to confirm or rule out asthma.
An airway responsiveness test is a test that measures how your airways react to an asthma trigger .
During the test, you'll usually be asked to breathe in a medication that will irritate or narrow your airways slightly if you have asthma. You'll then have a spirometry test to check if your breathing is affected.
In some cases, exercise may be used as a trigger instead of medication.
Sometimes it's useful to check for inflammation in your airways.
This can be done in two ways:
If your doctor thinks your symptoms may be triggered by an allergy, they may recommend allergy tests to find out what you're allergic to.
Common allergy tests include:
Tests can also be carried out to see if you are allergic or sensitive to substances known to cause work-related asthma . Find out more about diagnosing asthma at Asthma UK: diagnosing asthma.
Reliever inhalers, which are usually blue, are taken when needed to relieve asthma symptoms quickly.
They normally contain a medicine called a short-acting beta2-agonist, which widens the airways and makes breathing easier. They typically work for no more than 15 minutes or so.
Everyone with asthma should have a reliever inhaler, although you ideally shouldn't need to use it very often. You may not need it at all if you are using a regular preventer inhaler (see below).
Speak to your doctor or asthma nurse if you need to use it three or more times a week, as this means a preventer inhaler (see below) may be needed.
Reliever inhalers are generally very safe medicines and have few side effects as long as they're not used too much.
After using the inhaler, some people may experience:
These side effects aren't dangerous and should pass within a few minutes. Read more at Asthma UK: reliever inhalers.
Preventer inhalers, which are usually brown or orange, are used twice or occasionally once a day to stop asthma symptoms occurring.
They contain inhaled steroid medication , which works by reducing the inflammation (swelling) and sensitivity of the airways.
Preventer inhalers are usually recommended if you have asthma symptoms more than twice a week. It's important to use them regularly even if you don't have symptoms, because they keep the inflammation in the breathing tubes under control, and this can get worse again if you stop using your inhaler.
Preventer inhalers don't work straight away, so you'll need to keep using your reliever inhaler to begin with. You may also need to use your reliever inhaler if you do experience any occasional symptoms.
Speak to your doctor or asthma nurse if you continue to have frequent symptoms while using a preventer inhaler.
Preventer inhalers are very safe at usual doses, but they can cause side effects at high doses, especially with long-term use.
Possible side effects include:
Using a spacer (see How to use your inhaler below) can help prevent these side effects, as can rinsing your mouth or cleaning your teeth after using your inhaler. Read more at Asthma UK: preventer inhalers.
If your symptoms aren't well controlled with reliever and preventer inhalers, you may need one or more of the treatments below.
Long-acting reliever inhalers work in the same way as normal reliever inhalers, but their effects can last for up to 12 hours so they can be used less often.
They usually contain a medicine called a long-acting reliever (long-acting bronchodilator/long-acting beta2-agonist).
Long-acting reliever inhalers are always used alongside preventer inhalers, often in a single combined inhaler. This can allow your preventer dose to be lowered, while still keeping your symptoms under control.
Combination inhalers are usually purple, maroon or red.
Long-acting relievers can cause similar side effects to short-acting relievers, such as temporary shaking or cramps.
It's important never to take a long-acting reliever on its own without a preventer. This may temporarily relieve your symptoms, while allowing the inflammation in the breathing tubes to build up, which could result in a sudden severe asthma attack.
If you still have symptoms despite using a preventer inhaler and a long-acting reliever inhaler, your doctor may suggest taking tablets to control your symptoms.
The main tablets used for asthma are:
Leukotriene receptor agonists can cause tummy (abdominal) pain and headaches. Side effects of theophylline tablets include nausea, vomiting, tremors and palpitations.
Different people require different doses of theophylline for it to work best. Your doctor will periodically measure the level of medication in your blood to check it's not too high or too low. If it's too low, the medication may not work, and if it's too high, side effects are more likely.
If your asthma is still not under control, an asthma specialist may prescribe regular steroid tablets.
Steroids are powerful medicines that can reduce inflammation in the airways. They can be used in two ways:
Long-term or frequent use of steroid tablets can cause side effects, such as:
With the exception of increased appetite, which is a very common side effect, most of these unwanted effects are uncommon.
You'll be monitored regularly while taking steroid tablets to check for signs of any problems.
Omalizumab (brand name Xolair), is a new type of medication that can sometimes help prevent frequent, severe asthma attacks that are triggered by allergies. It's less effective at relieving persistent symptoms.
The National Institute for Heath and Care Excellence (NICE) recommends that omalizumab can be used in people over six years of age with allergy-related asthma who need continuous or frequent treatment with steroid tablets.
It's only available on prescription from an asthma specialist and isn't suitable for everyone with asthma.
It's given as an injection every two to four weeks. If your symptoms aren't under control within 16 weeks, treatment should be stopped. It may be continued indefinitely if it does help.
Side effects of omalizumab can include temporary pain, swelling, redness and itching where the injection is given.
Mepolizumab (brand name Nucala) is a new type of medicine that can help control severe asthma in some people.
NICE recommends it for some adults who have severe, difficult to control asthma that's associated with a high number of eosinophils in the blood.
Eosinophils are white blood cells that cause the breathing tubes that carry air in and out of the lungs to become swollen and sensitive in some people with asthma.
Mepolizumab reduces the number of these cells in the blood, which may reduce the number of bad asthma attacks you have and/or mean your dose of steroid tablets can be reduced or stopped.
It's given by injection once every four weeks. If it doesn't help after a year, the treatment will be stopped. If it does help, it can be used as a long-term treatment.
Common side effects of mepolizumab include headaches, back pain , and pain, redness and/or swelling where the injection is given.
Want to know more?
Bronchial thermoplasty is a procedure that is very occasionally used as a treatment for severe asthma.
It involves damaging some of the muscles surrounding the airways, which can help stop them becoming narrow.
The procedure is carried out either with sedation (where you're awake but take medication to help you relax) or under general anaesthetic (where you're asleep).
A bronchoscope (a long, flexible tube) is passed down to your lungs through your mouth or nose. Heat is then used to damage the muscles around the airways.
Three treatment sessions are usually needed, with at least three weeks between each session.
There's some evidence to suggest this procedure may reduce asthma attacks and improve the quality of life of someone with severe asthma.
But the long-term risks and benefits are not yet fully understood. There's a small risk it could trigger an asthma attack and cause other complications.
Make sure you discuss this procedure fully with your doctor or surgeon if it's offered.
Want to know more?
Not using inhalers correctly and/or forgetting to take asthma medication regularly are the main reasons people with asthma struggle to control their symptoms.
Your doctor or asthma nurse will show you how to use your inhaler properly, or how to help your child use theirs.
There are several different inhalers available, which are used in slightly different ways.
The two main types are:
Pressurised containers can be used by most people with asthma. Dry powder inhalers may not be suitable for people who find it difficult to inhale sharply and forcefully, such as young children, the frail and elderly, and those with persistent breathing difficulties.
It's important to ensure that you use your inhaler correctly, as this will make it easier to control your symptoms and will reduce the risk of any side effects.
Pressurised canister inhalers can work better if used with a spacer – a hollow plastic tube or container with a mouthpiece at one end and a hole for the inhaler at the other.
When using a spacer, the spray from the inhaler is released into the container, where it's held while you breathe in very slowly until your lungs are full. You then hold your breath for a few seconds so the medicine settles in your lungs.
Benefits of spacers include:
Spacers are usually recommended for children with asthma, but they should ideally be used by everyone who uses a preventer spray inhaler, especially if they need to take high doses.
Want to know more?
If it's possible you have asthma associated with your job, known as occupational asthma, you'll be referred to an asthma specialist to confirm the diagnosis.
If your employer has an occupational health service, they should also be informed, along with your health and safety officer.
Your employer has a responsibility to protect you from the causes of occupational asthma. It may sometimes be possible to:
But you may need to consider changing your job or relocating away from your work. It's best to do this within 12 months of your symptoms developing if possible, to reduce the risk of your asthma becoming a long-term problem.
Want to know more?
A number of complementary therapies have been suggested as possible treatments for asthma, including:
However, there's little evidence that any of these treatments, other than breathing exercises, are effective.
There is some evidence that breathing exercises can improve symptoms and reduce the need for reliever medicines in some people, although they shouldn't be used instead of your medicine.
Find out more at Asthma UK: complementary therapies.
It's important to take any prescribed medication regularly, as this can help keep your symptoms under control and prevent severe asthma attacks.
It's also important to use any inhalers and spacers you may have been prescribed properly. Make sure your doctor or practice nurse shows you how to use your inhalers correctly.
Check with your doctor or asthma nurse if you plan to take any over-the-counter remedies, such as painkillers or nutritional supplements. These can sometimes interfere with your medication.
Speak to your doctor or asthma nurse if you have any concerns about the medication you're taking, or if you're experiencing any side effects.
If you have asthma and you smoke, stopping smoking can significantly reduce how severe and frequent your symptoms are.
If you think you need help to stop smoking, you can contact your doctor about the stop smoking medications available.
Find more tips to stop smoking.
Exercising regularly is as important for people with asthma as everyone else. Aim to do at least 150 minutes of moderate aerobic activity a week, such as fast walking or cycling.
Although exercise can sometimes trigger your symptoms, this shouldn't happen once you're on appropriate treatment.
If you or your child has symptoms during or after exercise, speak to your doctor or asthma nurse. They may consider updating your personal asthma plan to help you keep your symptoms under control.
You may also be advised to:
If you have symptoms while you're exercising, stop what you're doing, take your reliever inhaler and wait until you feel better before starting again.
Read more about easy ways to exercise.
Most people with asthma can eat a normal, healthy diet.
Along with regular exercise, this can help you maintain a healthy weight, which may help keep your asthma symptoms under control, as well as reduce your risk of other health problems.
Some people may have food allergies that trigger their symptoms and will need to avoid these foods, but this is uncommon.
Read more about eating a balanced diet.
It's important to identify possible asthma triggers by making a note of where you are and what you're doing when your symptoms get worse.
Some triggers, such as air pollution, illnesses and certain weather conditions, can be hard to avoid. But it may be possible to avoid other triggers, such as dust mites, fungal spores, pet fur and certain medications. Read more about indoor allergy prevention.
Speak to your doctor or asthma nurse for advice if you think you have identified a trigger for your symptoms.
Certain infections can trigger your symptoms if you have asthma.
Everyone with asthma is encouraged to have the annual flu jab and the one-off pneumococcal vaccination.
You can get these vaccinations at your doctor surgery or a local pharmacy that offers a vaccination service.
Asthma symptoms are often worse at night. 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 should help. But speak to them if you're having trouble getting to sleep.
Want to know more?
You'll have regular contact with your care team to monitor your condition.
These appointments may involve:
It's also a good opportunity to ask any questions you have or raise any other issues you'd like to discuss with your doctor or asthma nurse.
You may be asked to help monitor your condition between appointments. For example, you may be advised to check your peak flow reading if you think your symptoms may be getting worse.
Your personal action plan should say what to do if your symptoms get gradually or suddenly worse. Contact your doctor or asthma nurse if you're not sure what to do.
Cold weather is a common trigger for asthma symptoms.
Asthma UK advises the following measures to help you keep your symptoms controlled in the cold:
Want to know more?
Asthma shouldn't stop you from travelling, but you will need to take extra precautions when going on holidays and long trips.
You'll need to make sure you have enough of your medication with you and keep your reliever inhaler where you can get to it easily.
If you've not seen your doctor or asthma nurse for a while, it's a good idea to see them before you travel to review your personal action plan and make sure it's up-to-date.
Your doctor or asthma nurse can also advise you about travelling with asthma.
Want to know more?
Asthma doesn't affect your chances of having children and the vast majority of women with asthma will have a normal pregnancy.
Generally speaking, the treatment for pregnant women with asthma is the same as normal.
Most asthma medicines – particularly inhalers – are considered safe to take while pregnant or breastfeeding.
But speak to your doctor or asthma nurse for advice if you become pregnant or are planning a pregnancy because:
Want to know more?
Most children with well-controlled asthma can learn and participate in school activities completely unaffected by their condition.
But it's important to ensure the school has up-to-date written information about your child's asthma medicines, how much they take, and when they need to take them.
You may also need to supply the school with a spare reliever inhaler for your child to use if they experience symptoms during the school day.
Staff at the school should be able to recognise worsening asthma symptoms and know what to do in the event of an attack, particularly staff supervising sport or physical education.
Your child's school may have an asthma policy in place, which you can ask to see.
Want to know more?
Many people with long-term health conditions such as asthma experience feelings of stress, anxiety and depression .
You may find it helpful to talk about your experience of asthma with others in a similar position. Patient organisations have local groups where you can meet others who have been diagnosed with asthma and have undergone treatment.
If you feel you're struggling to cope, talk to your doctor. They will be able to give advice and support. Alternatively, you can find depression support services in your area.
Want to know more?
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.