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 in addition to your child’s usual asthma medicines, if their usual medicines, taken regularly and in the right way, aren’t dealing with their symptoms.

Airways - your child’s airways bring air into your child’s lungs and take carbon dioxide out. The airways include the nose, the mouth, the larynx (voice box), the trachea (wind pipe) 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, pet fur or insect bites. An allergy happens when the body’s immune system recognises and overreacts to something. Symptoms of an allergy can include itching, sneezing, wheezing, coughing, swelling or rash.

Allergic rhinitis - a common condition where the inside of your child’s nose gets inflamed if your child comes into contact with allergens like pollen, dust or pets. Typical 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.

Asthma - a long-term condition featuring inflammation, swelling and narrowing in the airways with typical symptoms of coughing, wheezing, chest tightness and breathlessness.

Asthma action plan - a treatment plan filled out by you and your child’s GP or asthma nurse where you record the medicines your child needs to take every day, and what to do if their symptoms get worse, including 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 - when your child’s asthma symptoms (coughing, wheezing, feeling breathless, tight chest) are getting worse and it’s hard for them to breathe, they’re having an asthma attack. They’ll need to use their reliever inhaler immediately to help things get back in control. Some children may need a ‘rescue’ dose of steroid tablets or emergency care. Some health professionals call this asthma ‘flare-up’ or ‘exacerbation’.

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, and preferably every six months.

Atopy/atopic - if your child is ‘atopic’ it means they’re more likely to get allergies like eczema, asthma and hay fever. This often runs in the family – doctors sometimes talk about ‘atopic families'.


Bronchiolitis - a respiratory tract infection caused by a virus that can affect babies and young children under two years old. If your child has had bronchiolitis a lot, they could be more at risk of developing 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 might be given a combination inhaler that combines two kinds of medicine: a long-acting reliever to relieve ongoing symptoms, such as breathlessness and a tight chest, and a corticosteroid preventer to help prevent inflammation in your child’s airways on an ongoing basis.

Corticosteroids - the types of steroids used to treat asthma by preventing inflammation in the airways. Your child’s preventer inhaler will usually contain a low dose of corticosteroid medicine. Corticosteroids copy those produced naturally in our bodies. They are completely different to the anabolic steroids associated with bodybuilders and athletes.

Croup - a childhood respiratory tract infection with typical symptoms of a ‘barking’ cough, a hoarse voice, and a noise when your child breathes in (called a stridor). A child with croup might also find it hard to breathe because their airways are swollen and inflamed.


Dander - tiny flakes of skin and fur which come off of 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 in either micrograms or milligrams that your child is prescribed based on their age and symptoms. 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) - Dry powder inhalers (DPIs) give the medicine in a dry powder form instead of a spray.

Dust mites - tiny insects found in dust which 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 mite’s droppings.

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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 Prof 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 like 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 the lungs can also get inflamed in asthma. Inflammation in your child’s airways is an asthma symptom controlled 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 allow the asthma medicines to get right into the lungs where it needs to be.

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


Long-acting reliever inhaler - an add-on treatment prescribed to 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 reliever keeps your child’s airways open by relaxing the muscles around them helping them breathe more easily.

Leukotriene receptor antagonists (LTRAs) – a non-steroid add-on treatment prescribed to help your child’s asthma symptoms by preventing inflammation in the airways. LTRA’s are normally the first choice add on treatment for children under five years old.

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


Mask - some spacers come with a face mask to help younger children (under three) 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.

Metered Dose Inhaler (MDI) - when your child presses their metered dose inhaler the medicine in it is released as a fine spray.

Montelukast - is a leukotriene receptor antagonist add-on treatment used to prevent inflammation in the airways.

Mucus - sticky substance produced by the mucous membranes lining your child’s airways in reaction to an allergen, infection or virus. If your child has a cold for example their nose will probably be 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.

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Nebuliser - a device often used in hospitals for children with 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 - 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 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. This provides a benchmark score which, alongside symptoms, can help parents see when their child’s asthma is getting worse. Peak flow is only useful once your child can blow consistently well, usually after the age of around 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 might need.

Phlegm - a thick sticky substance (mucus) produced in the lungs, or the back of the 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 might 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.

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 them what medicine your child needs to take, how much they need to take, when, and for how long, and instructing the pharmacist to supply the medicine to your child. The information from the prescription will appear on the label of your child’s medicine.

Preventer - asthma medicine, usually in the form of a corticosteroid preventer inhaler, designed to prevent inflammation in your child’s airways. Your child needs to take their preventer medicine every day even when 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 might also use this word to let you know you how much medicine your child needs to take. For example ‘take two puffs morning and evening.’ 

Puffer - another word people sometimes call their 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 which helps your child’s airways relax and open up so it’s easier for your child to breathe.

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 affecting 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 what’s known as ‘perennial’ allergic rhinitis which means it affects them all year round, in response to an allergy like house dust mites, or pets. ‘Seasonal allergic rhinitis’, also known as hay fever, is 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.

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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. It is marketed as Ventolin which is how you might know it.

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 like pollen or pets, making their asthma symptoms worse.

Severe asthma - a type of asthma that affects five 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 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 the substance your child might 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 which 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 bodies. They can quickly stop the inflammation that leads to asthma symptoms.

Stridor - if your child has an infection called ‘croup’, this is the word used to describe the noise they make when they breathe in.

Suspected asthma - when your child has ‘suspected asthma’ it means they have symptoms which 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 over the age of six months 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 exercise. Your child may have more than one trigger.


Wheeze - this is the name for the sound your child might make when their asthma is not under control. It is sometimes quite hard to describe and parents describe it in different ways. UK guidelines describe it as ‘a continuous, high-pitched musical sound coming from the chest’.

‘Window of opportunity’ - this is a term used to describe 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.

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