Asthma in children

24 min read

What is asthma?

Asthma is a common long-term condition that can be effectively controlled in most children. The severity of asthma symptoms varies between children, from mild to severe.

Asthma affects the airways, the small tubes known as the bronchi, that carry air in and out of the lungs. If your child has asthma, the airways of their lungs are more sensitive than normal.

When your child comes into contact with something that irritates their lungs, known as a trigger (see below), their airways narrow, the lining becomes inflamed, the muscles around them tighten, and there is an increase in the production of sticky mucus or phlegm.

This makes it difficult to breathe and causes symptoms such as:

  • wheezing
  • coughing
  • shortness of breath
  • tightness in the chest

Asthma attack

A sudden, severe onset of symptoms is known as an asthma attack, or an acute asthma exacerbation. Asthma attacks can sometimes be managed at home but may require hospital treatment. They are occasionally life threatening.

Read more about the

symptoms of asthma in children

Causes of asthma

The exact cause of asthma is not yet fully understood. Asthma often runs in families and a child is more likely to have asthma if one or both parents have the condition.

There are also a range of asthma triggers, although everyone’s asthma is different and people may have several triggers.

An upper respiratory tract infection, such as a cold or flu is the most common trigger of an asthma attack. Other common triggers include:

  • exercise, especially in cold weather
  • an allergy to and contact with house dust mites, animal fur, grass and tree pollen
  • exposure to air pollution, especially tobacco smoke

Read more about the

causes of asthma in children

Asthma is more common in young boys than young girls. However, this changes as children get older and, after

, asthma is more common in girls.

During teenage years, the symptoms of asthma may disappear. However, asthma can return in adulthood.

It can be difficult to diagnose asthma in children as many other conditions can cause similar symptoms.

Read more about

how asthma is diagnosed in children

Treating asthma in children

While there is no cure for asthma, there are effective treatments that can help control the condition. Treatment is based on two important goals:

  • relieving symptoms
  • preventing future symptoms and attacks from developing

Treatment involves a combination of medicines, a personal asthma action plan and avoiding potential asthma triggers.

Read more about

how asthma in children is treated

It is important for your child to continue using their prescribed medication, with regular reviews. This will help to keep asthma symptoms under control as your child gets older.

There are also several lifestyle changes that may help you and your child to manage their asthma. With support from schools, there is no reason why a child with asthma cannot take a full part in education and exercise.

Read more about

living with asthma

Asthma symptoms

The symptoms of asthma can range from mild to severe. When asthma symptoms get significantly worse it is known as an asthma attack.

The common symptoms of asthma include:

  • feeling breathless (sometimes gasping for breath)
  • a tight chest, like a band tightening around it
  • wheezing (there may be a whistling sound when your child breathes)
  • coughing, particularly at night and early morning
  • attacks triggered by exercise, exposure to allergens and other triggers

Symptoms vary between children and they may have one or more of these symptoms. If symptoms become worse during the night or with exercise, your child's asthma may not be well controlled. Take your child to see their doctor or asthma nurse.

Asthma attack

A severe asthma attack usually develops slowly, taking 6 to 48 hours to become serious. However, for some children, asthma symptoms can get worse quickly.

Be aware of any signs of worsening asthma in your child. These may include:

  • your child becoming more wheezy, tight chested or breathless
  • the reliever inhaler (usually blue) not helping as much as usual
  • a drop in peak expiratory flow rate (see
    diagnosing asthma in children
    for more information)

If you notice your child's symptoms getting worse, do not ignore them. Contact your doctor or asthma clinic, or consult their asthma action plan, if they have one.

Signs of a severe asthma attack include:

  • the reliever inhaler does not help symptoms at all
  • the symptoms (wheezing, coughing, tight chest) will be severe and constant
  • breathing very fast and too breathless to complete a sentence in one breath or too breathless to talk or feed
  • a racing pulse
  • feeling agitated or restless
  • lips or finger nails may turn blue

Call for an ambulance if your child has severe symptoms of asthma.

You may be advised to give extra doses of the reliever inhaler while you are waiting for the ambulance.

What causes asthma in children?

There is no single known cause of asthma. However, certain things may increase the likelihood of your child developing asthma.

This can be due to your child’s genes or their environment, particularly in early life.

Increased risk

The likelihood of developing wheezing and asthma is increased if:

  • there is a family history of asthma or other related allergic conditions (known as atopic conditions) such as
    hay fever
    or a
    food allergy
  • your child develops another atopic condition such as eczema, hay fever or a food allergy
  • your child develops acute
    (a lung infection, common in babies, that is caused by a virus )
  • your child is exposed to tobacco smoke, particularly if the child's mother smokes during pregnancy
  • your child was born prematurely
  • your child was born with a low birth weight (less than 2kg or 4.5lb)

Asthma triggers

Asthma can have a range of triggers, but they do not affect everyone in the same way. Once you know what your child’s asthma triggers are, you can try to avoid them.

Triggers include:

  • Airway and chest infections – Upper respiratory infections, which affect the upper airways, are often caused by cold and
    viruses and are a common trigger of asthma.
  • Allergens – Pollen, dust mites, animal fur or feathers, for example, can all trigger asthma.
  • Airborne irritants – Cigarette smoke, chemical fumes and atmospheric pollution may trigger asthma.
  • Medicines – The class of painkillers called
    non-steroidal anti-inflammatory drugs (NSAIDs)
    , including
    , can trigger asthma for some people, although are fine for most. Children under 16 years of age should not be given aspirin.
  • Emotional factors – Asthma can be triggered by emotions, such as stress or laughing.
  • Foods containing sulphites – Sulphites are naturally occurring substances found in some food and drink. They are also sometimes used as a food preservative. Food and drinks that are high in sulphites include concentrated fruit juice, jam, prawns and many processed or pre-cooked meals. Most children with asthma do not have this trigger, but some may.
  • Weather conditions – A sudden change in temperature, cold air, windy days, poor air quality, and hot, humid days are all known triggers for asthma.
  • Indoor conditions – Mould or damp, house dust mites and chemicals in carpets and flooring materials may trigger asthma.
  • Exercise – Sometimes, people with asthma find their symptoms are worse when they exercise.
  • Food allergies – Although uncommon, some people may have allergies to nuts or other food items, known as an
    anaphylactic reaction
    . If so, these can trigger severe asthma attacks.

What happens during an asthma attack?

During an asthma attack:

  • the bands of muscles around the airways tighten
  • there is increased inflammation in the linings of the airways and they become swollen
  • the airways produce sticky mucus or phlegm, which can further narrow the airways

This narrows the passages of the airways, making it more difficult for air to pass through (in other words, making it more difficult to breathe). This can cause the characteristic wheezy noise. However, not everyone with asthma will wheeze. In a life-threatening attack, there may not be a wheezy sound.

An asthma attack can happen at any time. However, there are usually warning signs for a couple of days before, such as symptoms getting worse, especially during the night, and an increased need to use the reliever inhaler.

Asthma can sometimes be life threatening. See

treating asthma in children
for more information about how to manage your child’s asthma. Speak to your doctor or asthma nurse for further advice.

If your child or someone else is having a severe asthma attack and are unable to breathe, dial 999 immediately to request emergency medical treatment.

Diagnosing asthma in children

Asthma can be difficult to diagnose in young children because many other conditions can cause similar symptoms.

Most children develop the symptoms of asthma by the time they reach school age. Some children also have other allergic (atopic) conditions such as

hay fever

There is no simple test to diagnose asthma, but certain combinations of symptoms and signs make it likely that your child has asthma.

Seeing your doctor

Your doctor will ask about your child's symptoms and listen to their chest. They will want to know when and how often your child has symptoms and if you have noticed anything that might trigger them. The doctor will also ask about your child's medical history and whether there is a history of allergic conditions in your family.

If your doctor suspects your child may have asthma, a number of tests can be carried out to confirm the diagnosis.

Sometimes, children may be given an asthma inhaler as a trial treatment. If this helps their symptoms, the child probably has asthma. However, asthma medicines can be relatively ineffective in infants and young children, so a negative response may not definitely rule out asthma.


To assess how well your child’s lungs work, a breathing test called spirometry is carried out at the doctor surgery. This test can only be done reliably in children over the age of five.

Your child will be asked to breathe into a machine called a spirometer. The spirometer takes two measurements: the volume of air that your child can breathe out in one second (called the forced expiratory volume in one second or FEV1) and the total amount of air that your child can breathe out (called the forced vital capacity or FVC).

Your child may be asked to do the test a few times to get a consistent reading.

The readings are compared with normal measurements for children of your child’s age. This will show if your child’s airways are obstructed.

Sometimes, an initial set of measurements is taken, and then your child is given a medicine to open up the airways (a reliever inhaler). Another reading is then taken. If the reading is much higher after taking the medicine, this suggests your child has asthma.

Peak expiratory flow rate test

A small hand-held device, known as a peak flow meter, can also be used to measure whether the lung airways are narrowed. The peak flow meter measures the highest flow of air that we can blow out of our lungs during one breath. This is called the peak expiratory flow rate (PEFR).

You may be given a peak flow meter to take home and a diary to record measurements of your child’s peak flow. Your child’s diary will also have a space for you or your child to record their symptoms. This will help you recognise when your child’s asthma is getting worse.

The PEFR test is only suitable for children over five years of age.

Other tests

Some children may need more tests. Additional tests may confirm the diagnosis of asthma or may help diagnose a different condition that causes symptoms similar to those of asthma. The results of these tests will help you and your doctor plan your child’s treatment.

Airway responsiveness tests

This test is used to see how the airways react when stimulated. The most common test of this type in children is an exercise test.

Your child will blow into a peak flow meter or a spirometer and then be asked to run as hard as they can for a few minutes. After the run, the breathing tests will be repeated. A significant decrease in the measurements may indicate your child has asthma.

Tests of airway inflammation

These tests are normally done in a hospital asthma clinic.

  • Phlegm sample – the doctor may take a sample of phlegm to check whether there is inflammation in the lungs.
  • Nitric oxide concentration – as your child breathes out, the level of nitric oxide in the breath is measured. A high level of nitric oxide can be a sign of airway inflammation.

Allergy testing

Skin testing or a

blood test
can sometimes help establish whether your child’s asthma is associated with specific allergies, such as allergies to dust mites, pollen and foods.

Treating asthma in children

Personal asthma action plan

As part of the initial assessment, you and your child should be encouraged to draw up a personal asthma action plan with your doctor or asthma nurse. The plan includes information about your child's asthma medicines. If your child has been admitted to hospital because of an asthma attack, you should be offered a written action plan (or the opportunity to review an existing action plan) before you go home.

As your child gets older, it is important for them to be able to recognise the signs and symptoms of their asthma, and how to effectively manage their condition. Both you and your child should be shown how to recognise when their symptoms are getting worse and the appropriate steps to take. You should also be given information about what to do if they have an asthma attack.

You and your child should review their personal asthma action plan with their doctor or asthma nurse at least once a year, or more frequently if their symptoms are severe or not well controlled.

As part of their asthma management, your child may be given a diary card and sometimes a peak flow meter to monitor their symptoms and the effects of treatment.

Taking asthma medicines


Asthma medicines are usually taken using inhalers. These are devices that deliver the drug directly into the airways through your child’s mouth when your child breathes in. Inhaling is an effective way of taking an asthma medicine as it goes straight to the lungs, with very little ending up elsewhere in the body. This means a smaller dose can be taken with fewer side effects.


Most young children find using inhalers difficult, so a spacer may be used. Spacers are large plastic or metal containers that have a mouthpiece at one end and a hole for the inhaler at the other. The medicine is ‘puffed’ into the spacer by the inhaler and it is then breathed in through the spacer mouthpiece. Children under the age of three have the spacer attached to a face mask rather than a mouthpiece, this makes it easier for them to breathe in the medicine. Spacers are also good for reducing the risk of

in the mouth or throat, which is an occasional side effect of inhaled steroid medicines. Steroid inhalers should always be taken with a spacer.

Reliever inhalers

Reliever inhalers are taken as soon as asthma symptoms develop. The inhaler, also known as a reliever, contains a medicine called a short-acting beta2-agonist. This will relieve the symptoms of asthma. Relievers work fast by relaxing muscles surrounding the narrowed airways. This allows the airways to open wider, making it easier to breathe. Examples of reliever medicines include salbutamol and terbutaline. They are generally safe medicines with few side effects.

If your child's symptoms are mild and do not occur often, they will just be given a reliever inhaler. Reliever inhalers are usually blue.

Preventer inhalers

Preventer inhalers work over time to reduce the amount of inflammation and ‘twitchiness’ in the airways and prevent asthma attacks occurring. Your child will normally be recommended to take their preventer inhaler every day to prevent symptoms. Your child will need to use their preventer inhaler daily for some time before they gain the full benefit. They should still use their reliever inhaler to relieve symptoms.

The preventer inhaler contains a medicine called an inhaled corticosteroid. Examples of preventer medicines include beclometasone, budesonide and fluticasone. Preventers are usually brown, red or orange.

Preventer treatment is normally recommended if your child:

  • has asthma symptoms more than twice a week
  • wakes at least once a week due to asthma symptoms
  • has to use a reliever inhaler more than twice a week

Inhaled corticosteroids (preventers) occasionally cause fungal infections (oral thrush) in the mouth and throat. Your child should rinse their mouth thoroughly after inhaling a dose. For more information on side effects, see below.

Other treatments and ‘add-on’ therapy

Long-acting reliever inhaler

If your child's asthma does not respond to treatment, the doses of their preventer inhaler can be increased if agreed with their healthcare team. If this does not control your child’s asthma symptoms, you may be given a different inhaler containing a medicine called a long-acting bronchodilator or long-acting beta2-agonist (LABA). Examples of LABAs include formoterol and salmeterol. LABAs are given in an inhaler that combines an inhaled steroid and a long-acting bronchodilator in a single device. It is known as a combination inhaler. LABAs work in a similar way to short-acting relievers, but their effects last up to 12 hours. Examples of combination inhalers include Seretide and Symbicort. These are usually purple or red and white.

If your child is under two years of age and has frequent symptoms, they should be referred to a specialist in children's asthma.

Other preventer medicines

If treatment of your child’s asthma is still not successful, additional preventer medicines will be tried. Two possible alternatives are:

  • Leukotriene receptor antagonists – this medicine, in the form of a chewable tablet or granules, can be added to food and works by blocking a chemical reaction that can lead to inflammation of the airways.
  • Theophyllines – this medicine, in the form of a tablet, helps widen the airways by relaxing the muscles around them.

In rare cases, if your child’s asthma is still not under control, they may be prescribed regular oral steroids (steroid tablets). This treatment should be supervised by a specialist in children's asthma (a respiratory paediatrician). Long-term use of oral steroids carries possible serious side effects, so is only used once other treatment options have been tried. See below for more information on the side effects of steroid tablets.

Occasional use of oral steroids

Most children only need to take a course of oral steroids for three to five days to treat an asthma attack.

Side effects of treatments

Your doctor or nurse will discuss with you the need to balance control of your child's asthma with the risk of side effects, and how to keep side effects to a minimum.

Side effects of relievers

Relievers (short-acting beta2 agonists) are safe and effective and have few side effects. The main ones include a mild shaking of the hands, headache and muscle cramps. These usually only happen with high doses of reliever inhalers and do not last very long.

Side effects of preventers

Preventers (corticosteroids), which may be given for asthma as tablets, by injection or through inhalers, can cause a range of side effects. However, when a low-dose corticosteroid is given as a preventer using an appropriate inhaler device, side effects are rare. One side effect of an inhaled steroid given regularly as a preventer is a fungal infection (

oral candidiasis or thrush
) of the mouth or throat. Very occasionally, children also develop a hoarse voice. Using a spacer can help prevent these side effects. Your child should also rinse their mouth or clean their teeth after taking their preventer inhaler.

During the first year of treatment with an inhaled steroid reliever, there is often a slight slowing of growth. However, with standard doses, children achieve their expected normal adult height. Similarly, regular use of standard doses of a steroid inhaler for several years does not increase the risk of thinning of the bones or of bone fractures.

If your child uses a preventer inhaler for a long time at high doses, there is a small risk of the more serious side effects associated with long-term oral steroid use (see side effects of steroid tablets, below). Children receiving long-term treatment with high doses of an inhaled steroid should be reviewed in a hospital clinic by a specialist respiratory paediatrician.

Side effects of add-on therapy

Some regular treatments for asthma are added when preventer treatment with an inhaled corticosteroid alone does not fully control your child’s symptoms.

Long-acting relievers (long-acting beta2 agonists or LABAs) may cause similar side effects to short-acting relievers: a mild shaking of the hands, headache and muscle cramps. Your doctor can discuss the risks and benefits of this medication with you. As with all asthma treatment, your child should be monitored and reviewed regularly. If you feel your child is not benefiting from the use of the long-acting reliever, it should be stopped.

Leukotriene receptor agonists seldom cause side effects but have been known to cause stomach upsets, thirst, headache and occasionally nightmares.

Theophylline tablets are an effective add-on treatment for asthma but commonly cause side effects in children, including nausea, vomiting and stomach upset, headaches, irritability and sleep disturbance.

Side effects of steroid tablets

Children taking oral steroids for more than three months, or who take frequent courses of oral steroids (three to four times a year), are at risk of side effects, these can include:

It is rare for children to need long-term treatment with steroid tablets. Such children should be reviewed at a hospital clinic by a paediatric respiratory specialist. They will require regular examinations to check for the development of these side effects and careful monitoring of their growth in height and weight.

Asthma attacks

Your child’s personal asthma action plan will help you and them to recognise the symptoms of an asthma attack, what to do and when to seek medical attention.

Treatment of asthma attacks usually involves taking several extra doses of the reliever inhaler (which is most often blue). If the symptoms of your child's asthma attack worsen, they may need hospital treatment.

If your child is admitted to hospital with an asthma attack, they will be given high doses of reliever treatment by inhalation and a course of steroid tablets (or occasionally injections). They may also need oxygen to bring their asthma under control.

After an asthma attack, your child's personal asthma action plan will need to be reviewed and reasons for the asthma attack identified so that, if possible, a future one can be avoided.

Complementary therapies

A number of complementary therapies have been suggested for the treatment of asthma, including:

  • breathing exercises
  • traditional Chinese medicine
  • acupuncture
  • ionisers (a device that uses an electric current to charge or ionise molecules of air)
  • the Alexander technique (a training programme designed to change the way you move your body)
  • homoeopathy
  • dietary supplements

There is little evidence that any of these treatments, other than certain breathing exercises, are of benefit to children with asthma.

There is good evidence that breathing exercises taught by a physiotherapist, yoga, and the Buteyko method (a technique involving shallow breathing) can improve symptoms and reduce the need for reliever medicines in some people, although most of the work in this area has been done in adults and not children.

Living with asthma

Daily life

With the right treatment and management, asthma should not restrict your child’s life.


Symptoms at night are an indication that asthma is poorly controlled. Your child might wake up some nights coughing or with a tight chest. Poor sleep can affect your child’s behaviour and concentration, as well as their ability to learn.

Achieving good control of asthma using the treatment your doctor recommends will reduce symptoms, which means your child should sleep better.


Children and young people should do at least 60 minutes (one hour) of aerobic activity every day, which should include a mix of moderate-intensity (such as fast walking) and vigorous-intensity (for example running) activities. Children generally want to be active, so if they are reluctant to exercise it may be an indication their asthma is not fully controlled.

If your child has asthma symptoms during or after exercise, speak to their doctor or asthma nurse. It is likely they will review your child's general symptoms and personal asthma plan to make sure their asthma is under control.

The doctor or asthma nurse may also tell your child to:

  • Use a reliever inhaler (usually blue) 10-15 minutes before they exercise and again after two hours of non-stop exercise or when they finish.
  • Start with warm-up exercises.
  • Try to structure their exercise plan around short-burst activities.
  • Exercise in humid environments.
  • Breathe through their nose if possible to avoid excessively rapid and deep breathing (hyperventilation).
  • Cool down correctly once exercise is finished.

Keeping well

Some medical conditions, such as

, are known to aggravate asthma. In children with asthma and allergic rhinitis, treating the allergic rhinitis as well as the asthma can help bring the asthma under control.

Know their triggers

It is important, where possible, to identify the triggers of your child's asthma by making a note of when symptoms get worse and, sometimes, using their peak flow meter during exposures to certain situations. Some triggers, such as air pollution, viral illness or certain weather conditions, can be hard to avoid. Other triggers, such as dust mites, fungus spores or pet fur, can sometimes be avoided.


Most children with well-controlled asthma can learn and participate in their school’s activities completely unaffected by their condition. However, it is important to tell the school if your child has asthma and to make sure that they have information about your child’s asthma medicines.

You will need to supply the school with a 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 should have an asthma policy in place, which you can ask to see.

Complications of asthma

Quality of life

Poorly controlled asthma can have an adverse impact on your child's quality of life. The condition can lead to:

  • fatigue
  • under performance or absence from school
  • psychological problems, including stress, anxiety and depression

Children may also feel excluded from their school friends if they cannot take part in games, sports and social activities.

If you feel your child's asthma is seriously affecting their quality of life, contact your doctor or asthma clinic. Your child's personal asthma action plan may need to be reviewed.


Asthma is the most common long-term condition in children and it can be life threatening. Your child’s personal asthma action plan will help you and them recognise symptoms of an asthma attack, what to do and when to seek medical attention.

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.