Asthma glossary

Our A-Z glossary helps you get clear about key asthma words.

Whether it’s a medical word your child’s doctor or asthma nurse has used, or a new word you’ve come across on our website, our asthma A-Z glossary can help clear up any confusion.

A | B | C | D | E | G | H | I | L | M | N | O | P | R | S | T | W


Add-on treatment  medicines prescribed on top of your child’s usual preventer asthma medicines if they need extra help to get their symptoms under control. Usually prescribed if their normal medicines, taken regularly and in the right way, aren’t dealing with their symptoms.

Airways – your child’s airways bring air containing oxygen into your child’s lungs and take carbon dioxide out. The airways include the nose, the mouth, the voice box (larynx), the windpipe (trachea) and the bronchial tubes in the lungs. The bronchial tubes split off into smaller and smaller airways like the branches of a tree. In asthma, when we say that a child’s airways are inflamed, we’re talking about these bronchial tubes.

Allergy – a reaction by the body to certain foods or other substances such as pollen, pets or insect bites. An allergy happens when your body’s immune system overreacts to something. Symptoms of an allergy can include itching, sneezing, wheezing, coughing, swelling or a rash. The allergic reaction can also trigger asthma symptoms.

Allergic rhinitis – a common condition where the inside of your child’s nose gets inflamed if your child comes into contact with allergens such as pollen, dust or pets. Common symptoms include a blocked, itchy or runny nose, itchy eyes and scratchy throat. Allergic rhinitis can make asthma symptoms worse.

Antihistamines  medicines to ease allergy symptoms, available from your GP or a pharmacy (some cause drowsiness but the newer versions are less likely to make you feel sleepy).

Asthma – a long-term condition of the lungs that makes airways sensitive, more swollen (inflamed) and narrow. This causes the typical symptoms that may include coughing, wheezing, chest tightness and breathlessness.

Asthma action plan  a personal treatment plan filled out with a healthcare professional to keep the key information in one place and share with others. It shows you what medicines your child needs to take every day, how to spot if their symptoms get worse and what to do, plus what to do if your child has an asthma attack. Your child’s asthma action plan works best if it is written down and regularly updated so you can look at it in between appointments and know what to do.

Asthma attack  a nurse who’s had special training in the treatment and management of asthma. They may work in a GP surgery or in a hospital clinic.

Asthma nurse  a nurse who’s had special training in the treatment and management of asthma.

Asthma review  an asthma appointment with your child’s GP or asthma nurse to check your child’s asthma medicines are working well for them, update your child’s written asthma action plan and check their inhaler technique. Children should have a full asthma review at least once a year.

Atopy/atopic  if your child is ‘atopic’ it means they’re more likely to get allergies like hay fever. This often runs in the family – doctors sometimes talk about ‘atopic families’. If you have allergies you’re also more likely to get conditions such as eczema and asthma.


Bronchiolitis  an infection of the lower respiratory tract (the airways and lungs) caused by a virus that mostly affects babies and young children under two years old. If your child has had bronchiolitis a lot, they could be more at risk of getting asthma as they get older.

Bronchodilators  a group of asthma medicines that relax and open up the airways, making breathing easier. Your child’s blue reliever inhaler is one of these.


Combination inhaler  your child may be given a combination inhaler that has two kinds of medicine in it to help control their asthma symptoms. There are different combination inhalers containing different combinations of medications. If you have asthma, the combination must contain an inhaled corticosteroid. The other medicine will be a long-acting bronchodilator.

Corticosteroids  the types of steroids used to treat asthma by keeping down the inflammation (swelling) in sensitive asthma airways. Your child’s preventer inhaler will usually contain a low dose of corticosteroid medicine. Corticosteroids in these preventer inhalers are similar to the natural steroids that your body makes naturally. They are usually prescribed in low doses that go straight to where they are needed in the airways.

Croup  a childhood infection that affects the airways. There’s usually a barking cough and a harsh, grating sound when they breathe in (called a ‘stridor’). A child with croup may also find it hard to breathe because their airways are swollen and inflamed.


Dander  tiny flakes of skin that come off animals including pets such as cats, dogs and guinea pigs. The animal’s dander, urine and saliva all contain pet allergens responsible for symptoms in children with an allergy to pets.

Diagnosis  the confirmation of an illness or health condition based on your child’s symptoms, their family and medical history, and any test results.

Difficult to control asthma  asthma that’s not well controlled for a number of reasons including not taking preventer medicines as prescribed and discussed with your GP or asthma nurse, other allergies making things worse, or being around cigarette smoke.

Dose  the amount of medicine that your child takes each time they use their medicines as prescribed (usually in either micrograms or milligrams – or even ‘puffs’). Your GP will use the lowest possible dose to deal with your child’s symptoms, and regularly review the dose prescribed.

Dry powder inhalers (DPIs)  these inhalers give the medicine in a dry powder form instead of a spray.

Dust mites  tiny insects found in dust that collects in mattresses, carpets, soft toys, pillows and beds. If your child has an allergy to dust it’s actually an allergy to the dust mites’ droppings.

Back to top


Exacerbation  healthcare professionals sometimes use this word to describe an asthma attack – when your child’s asthma symptoms (coughing, wheezing, feeling breathless, tight chest) are getting worse and they need to use their reliever inhaler urgently to help things get back in control. Some children may need a ‘rescue’ dose of steroid tablets or emergency care.


GP  stands for General Practitioner. Your child’s GP is the doctor they see at your local doctor’s surgery. GPs give general medical advice on a whole range of health issues, and prescribe medicines and give advice on living with and managing long-term health conditions.


Hay fever  an allergic reaction to pollen. Hay fever is also known as seasonal allergic rhinitis. If your child has hay fever it can make their asthma symptoms worse.

Healthcare professional  someone trained to diagnose, treat, prevent and give advice about any illness or long-term condition. A GP, hospital doctor, asthma nurse, midwife, and pharmacist are all examples of healthcare professionals.

Healthcare team  the healthcare professionals involved in your child’s care, such as your child’s GP and asthma nurse, and any other specialists they see for their asthma.

‘Hygiene hypothesis’  a theory put forward in a 1989 study by Professor David Strachan, which blames the rise in allergies on children being brought up in an environment that’s too ‘clean’ without coming into contact with germs and infections.


Immune system  your child’s immune system comes to the rescue if your child gets a virus or a cut or comes into contact with harmful germs. It swings into action to protect them against infection. If your child has an allergy to something, the symptoms they get, such as sneezing and coughing, are because of their immune system over-reacting to the substance they’re allergic to.

Inflammation  redness and swelling in the body tissues. The red, angry area around a spot, for example, is inflamed. But your lungs can also get inflamed when you have asthma. Inflammation in your child’s airways causes the symptoms of coughing, wheezing and breathlessness, and can trigger asthma attacks. It can be prevented by using a preventer inhaler every day, even when your child is well.

Inhaler  a device used to deliver asthma medicine to your child’s lungs by breathing it in. Inhalers are considered the best way to treat asthma as they help the asthma medicines to get right into the lungs where they need to be. There are many different types of inhaler. Your healthcare provider should help you find one that suits you and your asthma depending on the medicines, the dose, the frequency and the device. You should check your inhaler technique regularly as small errors can have a big impact on how well the medicines work.

Inhaler technique  the way your child uses their inhaler is known as their ‘technique’. A good inhaler technique is important as it helps medicine get right into their lungs where it’s needed, instead of ending up at the back of their throat or in their mouth.


Leukotriene receptor antagonists (LTRAs) – a non-steroid add-on treatment (meaning it’s taken alongside their other asthma medicines) prescribed to help your child’s asthma symptoms by preventing inflammation in their airways. LTRAs are normally the first choice add-on treatment for children.

Long-acting Beta 2 agonists (LABAs)  LABAs such as salmeterol and formoterol are used as add-on preventer therapies. They should always be prescribed with a regular steroid, ideally in the same inhaler.

Long-acting bronchodilator  an add-on treatment for children aged five and older in addition to their usual asthma medicines, and taken alongside them. It helps with asthma symptoms that are not being well controlled with the usual medicines. A long-acting bronchodilator keeps your child’s airways open by relaxing the muscles around them, helping your child to breathe more easily. There are three types of long-acting bronchodilator: long-acting Beta 2 agonists (LABAs), long-acting muscarinic receptor antagonists (LAMAs) and theophylline.

Long-acting muscarinic receptor antagonists (LAMAs) – LAMAs such astiotropium are mainly prescribed for people with COPD (chronic obstructive pulmonary disease) but are sometimes helpful for people with asthma too.

Lungs  large organs in the chest used for breathing. Our lungs take in oxygen from the air we breathe via the airways, and remove the waste product carbon dioxide from our body.


Monoclonal antibodies (mAbs)  are targeted biological medicines that can help some children with severe asthma, a kind of asthma that is often not manageable with usual asthma treatments. mAbs work by blocking the activity of some of the immune system chemicals that trigger inflammation in your child’s airways. This means they may not get their usual asthma symptoms as often, or they may be milder, and they’ll be less likely to have an asthma attack

Mask  some spacers come with a face mask to help younger children breathe in their asthma medicines easily, until they can use a spacer without a mask. The mask gives a good seal over the child’s mouth and nose so they get the full benefit of the medicine as they breathe in. You should check with your pharmacist that it fits correctly.

Metered Dose Inhaler (MDI)  when your child presses their metered dose inhaler, it squirts out the medicine in a fine spray.

Montelukast  a Leukotriene Receptor Antagonist (LTRA) add-on treatment used to keep down the swelling (inflammation) in sensitive asthma airways.

Mucus  sticky substance that lines your child’s airways – not just their nose. It’s produced to help trap germs, viruses, pollution and allergens. That’s why getting a cold usually means your child’s nose is full of mucus. The airways in the lungs of a child with poorly controlled asthma produce more mucus than the airways of a child without asthma.

Back to top


Nebuliser  a device often used in hospitals for children having a severe asthma attack. It changes a liquid form of a drug into a mist so your child can breathe it in more easily and in higher doses.


Oral steroids  a medicine that reduces swelling and inflammation, usually prescribed on a short-term basis when your child needs to get their asthma back in control, maybe because they’ve had a chest infection or their asthma symptoms have flared up badly. An example of an oral steroid is prednisolone which can be taken in tablet, soluble tablet or liquid form.


Peak flow  the measurement of how much and how fast your child can breathe out. Your child’s peak flow ‘score’ gives a clue to how well their lungs are working. Some people record their child’s peak flow scores over time to see a pattern and find out what their child’s personal best peak flow score is. Then they can compare scores to this best score to see if it drops – which is a signal that their asthma could be getting worse, especially if other symptoms are coming back too. Peak flow is only useful once your child can blow into the peak flow meter gadget consistently well, usually after the age of about five.

Peak flow meter  a hand-held device that measures peak flow. Your child blows into a tube attached to the meter to record their peak flow measurement.

Pharmacist  someone who is trained in the use of medicines and can give you advice about your child’s prescriptions and any over-the-counter medicines your child may need.

Phlegm  a thick sticky substance (mucus) produced in your lungs, or the back of your throat. Phlegm is what your child coughs up when they have a wet cough.

Pollen  a very fine powder produced by grass, trees, weeds and some flowers. If your child is allergic to pollen they may have a stuffy or runny nose, sore eyes and an itchy throat. An allergy to pollen is known as seasonal allergic rhinitis or hay fever. It can make asthma symptoms worse.

Prednisolone  an oral steroid prescribed either as tablets, soluble tablets or as a liquid to help when your child’s symptoms get worse.

Prescription  written instruction from your child’s doctor, nurse or GP to the pharmacist telling the pharmacist to supply the medicine to your child. It tells them what medicine your child needs to take, how much they need to take, when, and for how long. This same information will be put on the label of your child’s medicine.

Preventer  asthma medicine, usually in a preventer inhaler, designed to keep down inflammation (swelling) in your child’s sensitive airways. Your child needs to take their preventer medicine every day, even when they’re well, to keep their asthma under control.

Puff  a word people sometimes use to describe the action of using their inhaler and breathing in their asthma medicine. Your GP or asthma nurse may also use this word to let you know how much medicine your child needs to take. For example, ‘Take two puffs morning and evening.’

Puffer  another word for asthma inhaler.


Reliever  an asthma inhaler, usually blue, used to relieve your child’s asthma symptoms quickly when they come on. Relievers contain a medicine that helps your child’s airways relax and open up, so it’s easier for them to breathe. If they take their preventer medicine every day they are less likely to need this blue one for ‘on-the-spot’ relief. Using a reliever inhaler three or more times a week is a sign that there is untreated inflammation (swelling) in your child’s airways, so if this is the case, make an appointment with your GP or asthma nurse.

Respiratory system  the parts of the body involved with breathing. It is made up of the lungs and the airways (see above), and the muscles that help your child breathe.

Respiratory tract infection  any infection of the respiratory system, usually caused by a virus. The common cold is an ‘upper’ respiratory tract infection affecting the nose, sinuses and throat. Children get a lot of these because their immune systems are still developing. A ‘lower’ respiratory tract infection affects the airways and the lungs, for example a chest infection.

Rhinitis  this is a common condition when the inside of your child’s nose gets inflamed. Typical symptoms include a blocked, itchy or runny nose, itchy eyes and scratchy throat. Rhinitis can make asthma symptoms worse. Some children may have this all year round (what doctors call ‘perennial’ allergic rhinitis). It’s often caused by allergic reactions to things that are around all year, like house dust mites, or pets. Hay fever is known as ‘seasonal allergic rhinitis’, because it’s only worse at certain times of the year, depending on which pollen allergen your child is allergic to. Rhinitis isn’t always in response to an allergy. It could come about with a cold, for example.

Back to top


Salbutamol  is the reliever medicine most children with asthma use when they have asthma symptoms. It opens up the airways, making it easier for your child to breathe. Common brand names for salbutamol inhalers include Airomir, Asmalal, Easi-Breathe, Easyhaler, Pulvinal, Salamol, Salbulin and Ventolin.

Seasonal allergic rhinitis  is also known as hay fever. Seasonal allergic rhinitis is worse at certain times of the year depending on which pollen allergen your child is allergic to.

Self-management  is what you do every day to look after your child’s asthma, making sure they take their asthma medicines, and looking out for any asthma symptoms. An asthma action plan is a self-management tool reminding you what medicines your child needs to take and when, and how you need to act if your child’s symptoms get worse.

Sensitive  a child with asthma could be described as having more ‘sensitive’ airways. This means their airways are more likely to get irritated and inflamed and react to triggers such as pollen or pets, making their asthma symptoms worse.

Severe asthma  a type of asthma that affects about four per cent of people with asthma. For someone with severe asthma the usual asthma medicines don’t work as well, and different medicines − and the support of a team of healthcare professionals and specialists − is often needed to keep their asthma under control.

Side effects  unwanted symptoms, such as feeling sick or drowsy, caused by medical treatment and medicines. Sometimes side effects are called ‘adverse reactions’. All medicines, including ones bought ‘over the counter’, have possible side effects, but not everyone will get them. You can check the possible side effects of any medicine your child is taking on the patient information leaflet that comes in the box with the medicine. Or you can ask your pharmacist or GP.

Skin prick testing  a safe and painless way to test for allergies. It involves putting a drop of liquid containing something your child may be allergic to onto their arm and gently pricking the skin under the drop with a needle to see if there’s any reaction. If your child is allergic to something, it will show as an itchy red bump.

Spacer  this is a hollow plastic or metal container with a mouthpiece at one end and a hole where you attach your child’s asthma inhaler at the other. Spacers help deliver your child’s asthma medicine into their lungs. Spacers are very useful for children because with a spacer your child doesn’t have to coordinate the pressing of the inhaler with breathing in and holding their breath, which younger children can find difficult to do.

Spirometry  this is a breathing or lung function test that shows how well your child’s lungs are working. It’s sometimes used for children over five years old to help diagnose asthma and also to see if their asthma medicines are working.

Steroids or corticosteroids  are a type of asthma medicine prescribed either as an inhaler, a course of tablets, or sometimes as an injection. Steroids used in asthma medicines are a copy of the substances produced naturally in our body to reduce swelling and can quickly stop the swelling of the airways (inflammation) that leads to asthma symptoms.

Stridor  if your child has an infection called croup, this is the word used to describe the barking cough and a harsh, grating sound they make when they breathe in.

Suspected asthma  when your child has ‘suspected asthma’ it means they have symptoms that point towards them having asthma, but a diagnosis is not possible at the moment.

Symptoms  the physical signs of an illness or a long-term condition. In asthma, the typical symptoms are cough, wheeze, tight chest and shortness of breath.


Theophylline  an add-on treatment sometimes given to children alongside their usual asthma medicines, whose asthma isn’t well managed with just their usual asthma medicines.

Trigger  anything that brings on your child’s asthma symptoms such as pollen, dust, and cold weather. Your child may have more than one trigger.


Wheeze  this is the name for the sound your child may make when their asthma is not under control. UK guidelines describe wheeze as ‘a continuous, high-pitched musical sound coming from the chest’.

‘Window of opportunity’  this is the time before an asthma attack when, with the right action, and following an asthma action plan, your child’s asthma attack can be avoided.

Back to top


Last updated August 2019

Next review due August 2022