Asthma
A complete, NICE NG245–aligned guide to asthma — covering what it is, how it affects the airways, inhaler types, the stepwise treatment approach, and how to manage your asthma online.
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Asthma: Symptoms, Triggers, Diagnosis and Treatment
A UK guide to asthma: what it is, the types, symptoms and triggers, how it’s diagnosed, how it’s treated under the 2024 NICE, BTS and SIGN guideline, and what to do in an attack.
Asthma attack? Get help now. Call 999 if your reliever isn’t helping, you’re too breathless to speak, eat or sleep, your breathing is getting faster, or your lips or fingertips are turning blue or grey. While you wait, sit up straight and take 1 puff of your blue reliever every 30 to 60 seconds, up to 10 puffs, through a spacer if you have one. If the ambulance hasn’t arrived after 10 minutes, repeat. Don’t complete an online consultation in an emergency.
Quick answer: Asthma is a common long-term condition in which the airways are inflamed and extra sensitive. Triggers such as colds, pollen, smoke or cold air make them swell, tighten and fill with mucus, causing wheezing, breathlessness, chest tightness and coughing. It’s diagnosed with tests such as FeNO and spirometry, and treated mainly with inhalers containing a steroid. It can’t be cured, but most people can control it well.
Already Have Asthma? Order Your Usual Inhaler
Access Doctor is a GPhC-registered pharmacy (#9011198). If you’re an adult with diagnosed asthma or COPD, a pharmacist independent prescriber reviews your online consultation and supplies your usual inhaler if it’s safe, and we let your GP know. Approved before 3pm, Monday to Friday? Dispatched the same day, by Royal Mail Tracked 48, Tracked 24 or Special Delivery guaranteed by 1pm next working day: you choose. Delivery is free on orders over £40.
Start Asthma Consultation →Who our online service is for. Access Doctor supplies asthma and COPD inhalers to adults aged 18 and over who already have a diagnosis, for the same inhaler, strength and dose they’re prescribed now, and we share the consultation with your GP. We can’t diagnose asthma or start or change treatment online. Children’s inhalers are managed by their GP or asthma nurse.
What Is Asthma?
Asthma is a common, long-term condition affecting the airways, the tubes that carry air in and out of your lungs. In asthma, the airways are inflamed and extra sensitive to certain triggers. When they meet a trigger, they narrow, swell and make extra mucus, which makes breathing difficult.
Asthma affects people of all ages and often starts in childhood, though it can begin at any age. Asthma + Lung UK has estimated that around 5.4 million people in the UK are treated for it, making it one of the most common long-term conditions GPs see.
There’s no cure, but asthma can be very well controlled. Most people who use their treatment correctly have few or no symptoms and a normal, active life. Between flare-ups, the airways of someone with well-controlled asthma usually work almost normally.
How Asthma Affects the Airways
In healthy airways, air flows freely through open tubes lined with smooth muscle. In asthma, several things happen when a trigger is met:
Inflammation
The lining of the airways becomes inflamed and swollen. This is why a daily preventer, which treats inflammation, matters even when you have no symptoms.
Bronchoconstriction
The muscle around the airways tightens, making them narrower. This is what a reliever inhaler quickly reverses.
Extra mucus
The airways make more mucus than usual, narrowing them further and causing a cough as the body tries to clear it.
Over-sensitivity
Already-sensitive airways overreact to things that wouldn’t affect someone without asthma, such as cold air or smoke.
Together, these cause the main symptoms: wheezing, breathlessness, chest tightness and cough. Breathing out is particularly hard. The narrowing usually improves with a reliever inhaler, and showing this reversibility is one way asthma is diagnosed.
Types of Asthma
Asthma isn’t a single disease. Doctors recognise several types, which can overlap:
| Type | Key features |
|---|---|
| Allergic (atopic) asthma | The most common type, especially in children and young adults. Triggered by allergens such as pollen, house dust mites, pets and mould, through an IgE allergic response. Often comes with eczema or hay fever. |
| Non-allergic asthma | Not driven by allergens. More common in adults, especially women. Triggered by infections, cold air, exercise, pollution and irritants. Can be harder to control. |
| Occupational asthma | Caused or made worse by something at work, such as flour, latex, isocyanates (in spray paints), hairdressing chemicals or animal proteins. Symptoms that improve at weekends or on holiday are a classic clue. Spotting it early and avoiding the cause matters, because continued exposure can cause lasting damage. |
| Exercise-induced symptoms | Airway narrowing during or after exercise, usually worst 5 to 10 minutes after stopping, especially in cold, dry air. Often a sign that asthma isn’t fully controlled. See our exercise-induced asthma guide. |
| Adult-onset asthma | Starts in adulthood, often with no history in childhood. Can be more severe and need more treatment than childhood asthma. |
| Cough-variant asthma | A persistent cough, often at night, may be the only symptom. |
| Severe (difficult-to-treat) asthma | Asthma that stays uncontrolled despite correct technique, regular use and high-dose treatment. Affects a small minority. Needs specialist assessment and may be treated with biologic injections; see our guide to advanced asthma treatments. |
Symptoms of Asthma
Asthma symptoms are typically variable (they come and go), reversible (they improve with treatment), and often worse at night or early in the morning. The four main symptoms are:
- Wheezing: a whistling or squeaking sound when you breathe, especially breathing out
- Breathlessness: during or after activity, at night, or when lying down
- Chest tightness: a squeezing, heavy or pressing feeling in the chest
- Coughing: often worse at night or early in the morning; it may be the only symptom
Not everyone has all four. Symptoms can disappear between flare-ups, which can make diagnosis harder. Some people have mild, occasional symptoms; others have symptoms most days that limit what they can do. See your GP about any wheeze, breathlessness or cough that keeps coming back.
Not all wheezing is asthma. COPD, vocal cord problems, heart failure, over-breathing (hyperventilation) and, rarely, something stuck in the airway can all cause similar symptoms. That’s why asthma needs a proper diagnosis with tests before treatment starts.
Common Asthma Triggers
A trigger is anything that irritates the airways and sets off symptoms. Triggers vary from person to person, and knowing yours is one of the best ways to prevent attacks. Our asthma triggers guide goes into detail.
| Category | Examples | Notes |
|---|---|---|
| Infections | Colds, flu, COVID-19, RSV | The most common trigger in adults and children |
| Allergens | House dust mites, pets, pollen (grass, tree, weed), mould spores | Mould spores peak in late summer and autumn; see our autumn asthma guide |
| Air quality | Tobacco smoke, vaping, traffic pollution, bonfire smoke, strong smells (cleaning products, perfume, paint) | Second-hand smoke makes asthma worse too |
| Weather | Cold or dry air, sudden temperature changes, damp, thunderstorms | Thunderstorm asthma: storms can break pollen into tiny particles that reach deep into the lungs |
| Exercise | Running and other aerobic activity, especially in cold air | Symptoms only with exercise often mean asthma needs a review |
| Medicines | Aspirin and anti-inflammatory painkillers (NSAIDs) such as ibuprofen and naproxen; beta-blockers, including some eye drops | Not everyone reacts to NSAIDs; if you’re unsure, ask a pharmacist. Always tell a prescriber you have asthma |
| Hormones | Periods, pregnancy, menopause | Asthma can improve, worsen or stay the same in pregnancy; see our asthma in pregnancy guide |
| Emotions and stress | Anxiety, laughing, crying, emotional upset | Strong emotions can change your breathing and set off symptoms |
If hay fever makes your asthma worse, see our guide to hay fever and asthma.
Who Gets Asthma?
The exact cause isn’t known, but several things make asthma more likely:
- a parent or sibling with asthma, eczema or hay fever
- having other allergic conditions yourself
- smoking, or being exposed to smoke as a child or before birth
- being born early or with a low birth weight
- certain jobs with exposure to dusts, chemicals or animal proteins
- being overweight
How Asthma Is Diagnosed
There’s no single test for asthma. Your GP or asthma nurse starts with your symptoms: when they happen, what sets them off, whether they wake you at night, and whether you have eczema, hay fever or a family history. If the history suggests asthma, the 2024 NICE, BTS and SIGN guideline (NG245) sets out these tests for adults, in order:
Blood eosinophils or FeNO
A blood test for eosinophils (a type of white cell), or a FeNO breath test that measures inflammation in the airways. Asthma is diagnosed if eosinophils are above the normal range or FeNO is 50 parts per billion or more.
Spirometry with a reliever
If the first test doesn’t confirm it, you blow into a spirometer before and after a reliever. An improvement in FEV1 (how much you can breathe out in one second) of at least 12% and 200ml supports asthma.
Peak flow diary
If spirometry isn’t available or is delayed, you measure your peak flow twice a day for 2 weeks. Variation of 20% or more supports asthma.
Bronchial challenge test
If asthma is still suspected, a specialist test checks how sensitive your airways are, by breathing in a substance such as methacholine or mannitol.
Our guide to how asthma is diagnosed explains each test and what to expect.
New symptoms need your GP, not an online pharmacy. Access Doctor’s online service is only for adults who already have a diagnosis and want a repeat of their usual inhaler. If you have new, unexplained breathlessness, wheeze or a persistent cough, see your GP for tests.
Asthma Control and Severity
Rather than labelling asthma as “mild” or “severe” once, current UK guidance focuses on whether it’s controlled. Asthma is treated as not controlled if you’ve needed steroid tablets for an attack, or you have frequent symptoms, such as using your reliever on 3 or more days a week or waking at night with asthma once a week or more.
Severity is judged by how much treatment you need to keep asthma controlled. Severe asthma is asthma that stays uncontrolled despite high-dose treatment taken correctly, and needs specialist care.
Asthma can change over time. Good control doesn’t mean you can stop treatment. When asthma has been well controlled, usually for at least 3 months, your GP or asthma nurse may reduce it, one step at a time.
Asthma Treatment in the UK
Older guidance described treatment as five numbered steps, starting with a blue reliever on its own. In November 2024, the joint NICE, BTS and SIGN guideline (NG245) changed this for adults and young people aged 12 and over:
| Stage | Treatment | When |
|---|---|---|
| Starting treatment | AIR: a combination inhaler with a low-dose steroid and formoterol, used only when you have symptoms | Newly diagnosed. If symptoms are frequent or you’ve had a severe attack, start on low-dose MART instead |
| Not controlled | Low-dose MART: the same kind of inhaler taken every day, plus extra doses for symptoms | Asthma not controlled on AIR |
| Still not controlled | Moderate-dose MART | Asthma not controlled on low-dose MART |
| Still not controlled | FeNO and blood eosinophil tests; specialist referral if raised, otherwise an 8 to 12 week trial of montelukast or a LAMA inhaler | Asthma not controlled on moderate-dose MART, with good technique and adherence |
| Specialist care | High-dose treatment, biologic injections, steroid tablets under specialist supervision | Severe asthma |
Before any change, your GP or asthma nurse should check your inhaler technique, whether you’re taking your treatment as prescribed, your triggers and the diagnosis. Many people with well-controlled asthma stay on a daily preventer and a separate reliever; you don’t have to switch, but you can ask about AIR or MART at your next review. Our asthma inhalers guide explains the pathway, and our guide to advanced asthma treatments covers montelukast, biologics and other add-ons.
A blue reliever on its own is no longer recommended. NG245 says no one with asthma should be treated with a short-acting reliever alone, and in April 2025 the MHRA reminded prescribers not to supply one without an inhaled steroid. Relying on a reliever lets inflammation carry on unnoticed and increases the risk of a severe attack.
Inhaler Types Explained
Reliever inhalers (SABA)
The blue inhaler most people associate with asthma. Salbutamol (such as Ventolin and Salamol) relaxes the muscle around the airways within about 5 minutes, and the effect lasts 4 to 6 hours. Relievers relieve symptoms only; they don’t treat inflammation. Needing one more than twice a week means asthma isn’t controlled and treatment should be reviewed.
Preventer inhalers (ICS)
Contain an inhaled corticosteroid (steroid) that reduces airway inflammation when taken every day. They’re often brown (such as Clenil Modulite) but colours vary between brands. The benefit builds up over days to weeks, so keep taking them even when you feel well. Rinsing your mouth after each dose reduces the risk of oral thrush. See our preventer inhaler guide and Clenil Modulite guide.
Combination inhalers (ICS + LABA)
Contain a steroid and a long-acting bronchodilator (LABA) in one device, such as Symbicort, Fostair or Seretide. Those containing formoterol can also be used as a reliever (AIR or MART). A LABA must never be used without a steroid in asthma.
Device types
Aerosol inhalers (pMDIs) need a slow breath timed with a press, ideally through a spacer. Dry powder inhalers need a fast, deep breath. Mistakes with technique are very common and stop the medicine reaching your lungs, so ask for your technique to be checked at every review. Our guide to how to use an asthma inhaler shows each step.
Our asthma inhalers guide covers every type, including which colour usually means what.
Ventolin: The Blue Reliever Inhaler
Ventolin Evohaler (salbutamol, 100 micrograms a puff, 200 puffs) is one of the most widely used relievers in the UK. It’s an aerosol inhaler, best used with a spacer. Key points:
- Usual adult dose: 1 or 2 puffs when needed, no more than 8 puffs in 24 hours; in an attack, follow the NHS steps below
- Starts working within 5 minutes and lasts 4 to 6 hours
- A reliever only: it doesn’t reduce airway inflammation
- Needing it more than twice a week means your asthma needs a review
- Salamol contains the same medicine, salbutamol, in a different inhaler
Our guide to what Ventolin is used for covers doses, side effects and technique, and our guide to Ventolin for shortness of breath explains when it helps and when breathlessness has another cause.
Asthma Attacks: Recognition and Response
An asthma attack is when symptoms get worse quickly and your reliever isn’t helping as it usually does, or the relief doesn’t last 4 hours. Warning signs:
- your reliever isn’t helping, or you need it more than every 4 hours
- wheezing, coughing or chest tightness getting worse
- too breathless to speak, eat or sleep
- breathing getting faster
- drowsiness, confusion or exhaustion, or lips or fingertips turning blue or grey: these are signs of a life-threatening attack
If you have an asthma action plan, follow it. Otherwise, the NHS advises:
Sit up straight and try to keep calm
Don’t lie down. If you’re helping someone else, stay with them and reassure them.
Take 1 puff of your reliever every 30 to 60 seconds, up to 10 puffs
Use a spacer if you have one. If you use a combination inhaler as your reliever (AIR or MART), follow your action plan.
Call 999
If you feel worse at any point, you don’t feel better after 10 puffs, or you don’t have your inhaler. Don’t drive yourself to hospital.
If the ambulance hasn’t arrived after 10 minutes, repeat step 2
Keep going until help arrives.
Afterwards, see your GP within 2 days
Even if you feel better, get an urgent appointment with your GP or asthma nurse, as the NHS advises, to review your treatment.
Call 999 immediately if your reliever isn’t working, you can’t speak in full sentences, your lips or fingertips are turning blue or grey, you feel drowsy or confused, or a child has stopped breathing, even briefly.
Our asthma attack guide explains the warning signs and what to do in more detail.
Asthma Self-Management
Written asthma action plan
A personal plan from your GP or asthma nurse that says what to take every day, what to do when symptoms get worse, and when to get emergency help. Having one reduces the chance of needing hospital care for asthma. Ask for one at your next review.
Annual review
Everyone with asthma should have a review with their GP or asthma nurse at least once a year, covering symptoms, inhaler technique, the right device, how you’re taking your treatment, and triggers. Book one sooner if your asthma isn’t controlled or after an attack.
Inhaler technique
Most people make at least one mistake with their inhaler, which means less medicine reaches the lungs. Ask for your technique to be checked at every review, and see our guide to using an asthma inhaler correctly.
Stopping smoking
Smoking makes asthma harder to control, makes steroid inhalers work less well and speeds up lung function decline. Stopping is one of the most useful things a smoker with asthma can do; your GP practice or local NHS stop smoking service can help.
Vaccinations
Most adults with asthma who use a steroid inhaler can have a free NHS flu vaccine every year. Ask your GP practice which other vaccines you’re eligible for.
A healthy weight
Being overweight is linked to harder-to-control asthma. Even modest weight loss can improve symptoms and may allow treatment to be reduced.
Getting Treatment: Your GP, the NHS and Online
Asthma is usually diagnosed and managed by your GP practice, often with an asthma nurse. That’s where to go for a new diagnosis, a change of treatment and your yearly review. Repeat prescriptions can usually be ordered through the NHS App.
- Prescription charges: NHS prescriptions are free in Scotland, Wales and Northern Ireland. In England a charge applies unless you’re exempt, and a prepayment certificate can save money if you need several items.
- Urgent advice: NHS 111 (NHS 24 on 111 in Scotland), or 999 in an emergency.
- Online: Access Doctor is a GPhC-registered pharmacy (registration number 9011198). If you’re an adult with diagnosed asthma or COPD, you can order the same inhaler you already use after an online consultation with a pharmacist independent prescriber, and we share it with your GP. See our asthma inhalers online or our guide to ordering an asthma inhaler online.
- Side effects: report them to a pharmacist or doctor, or to the MHRA through the Yellow Card scheme.
Need Your Usual Inhaler?
Access Doctor is a GPhC-registered pharmacy (#9011198). If you’re an adult with diagnosed asthma or COPD, a pharmacist independent prescriber reviews your online consultation and supplies your usual inhaler if it’s safe, and we let your GP know. Approved before 3pm, Monday to Friday? Dispatched the same day, by Royal Mail Tracked 48, Tracked 24 or Special Delivery guaranteed by 1pm next working day: you choose. Delivery is free on orders over £40.
Start Asthma Consultation →Asthma Health Guides
In-depth guides on every part of living with asthma:
Inhalers and treatment
Relievers
Living with asthma
Frequently Asked Questions
What is asthma?
Asthma is a long-term condition in which the airways are inflamed and extra sensitive. When something irritates them, they swell, tighten and make extra mucus, causing wheezing, breathlessness, chest tightness and coughing. Symptoms come and go and are often worse at night or early in the morning. It can’t be cured, but with the right treatment most people have few or no symptoms.
Is asthma curable?
There’s no cure, but asthma can be very well controlled. Most people who take their treatment as prescribed and use their inhaler correctly have few or no day-to-day symptoms. Some children’s asthma improves a lot as they grow up, but it can come back later in life.
What triggers an asthma attack?
Colds and other chest infections are the most common trigger. Others include house dust mites, pollen, pets, mould, cold air, smoke, air pollution, exercise, strong emotions, and some medicines such as aspirin, ibuprofen and beta-blockers. Triggers vary from person to person; our asthma triggers guide explains how to spot yours.
Can adults develop asthma for the first time?
Yes. Asthma can start at any age. In adults it’s often linked to work exposures (occupational asthma), hormonal changes, chest infections or new allergies. It can be missed because the symptoms are put down to other things. New wheeze, breathlessness or a cough that won’t go away needs a GP assessment and tests. See how asthma is diagnosed.
When should I call 999 for asthma?
Call 999 if your reliever isn’t helping, you’re too breathless to speak, eat or sleep, your breathing is getting faster, your lips or fingertips are turning blue or grey, or you feel drowsy or confused. While you wait, sit up and take 1 puff of your reliever every 30 to 60 seconds, up to 10 puffs, and repeat if the ambulance hasn’t arrived after 10 minutes.
What is the difference between a reliever and a preventer inhaler?
A reliever (usually blue, such as Ventolin) opens the airways within minutes but doesn’t treat the inflammation. A preventer contains an inhaled steroid that reduces inflammation when taken every day, even when you feel well. Combination inhalers contain a steroid and a long-acting bronchodilator, and some can be used as a reliever too (AIR or MART). Our asthma inhalers guide explains each type.
Can I get an asthma inhaler online?
Yes, if you already have a diagnosis. Access Doctor (GPhC reg. no. 9011198) supplies the same inhaler, strength and dose you already use to adults with diagnosed asthma or COPD, after a pharmacist independent prescriber reviews your online consultation, and we share it with your GP. New symptoms, a first inhaler or a change of treatment need your GP or asthma nurse. See our asthma inhalers online.
What is NICE NG245 and how does it guide asthma treatment?
NG245 is the UK asthma guideline published jointly by NICE, BTS and SIGN in November 2024. For adults and young people aged 12 and over, it replaced the old numbered steps: treatment starts with a combination inhaler containing a low-dose steroid and formoterol used when needed (AIR), moves to daily use plus extra doses (MART) if asthma isn’t controlled, and then to tests and specialist care. It says no one should be treated with a blue reliever alone. Our asthma inhalers guide explains the pathway.
Does asthma run in families?
It can. You’re more likely to have asthma if a parent or sibling has it, or if you or your family have other allergic conditions such as eczema or hay fever. Many people with asthma have no family history, though, and things like smoking, air pollution and some work exposures also raise the risk.
What is the difference between asthma and COPD?
Both cause breathlessness and wheeze, but asthma usually starts earlier, comes and goes, and the airway narrowing largely reverses with treatment. COPD (chronic obstructive pulmonary disease) is usually caused by smoking, develops after 35, and causes narrowing that doesn’t fully reverse and gets slowly worse. Some people have both. Spirometry and your history help your GP tell them apart.
References
- NICE, BTS and SIGN. Asthma: diagnosis, monitoring and chronic asthma management (NG245), November 2024. nice.org.uk
- NICE, BTS and SIGN. Pharmacological management of asthma in people aged 12 and over (NG245 algorithm), November 2024. sign.ac.uk
- NICE, BTS and SIGN. Objective tests for diagnosing asthma in adults (NG245 pathway). rightdecisions.scot.nhs.uk
- MHRA Drug Safety Update. Short-acting beta-2 agonists (SABA): reminder of the risks from overuse in asthma and changes in the SABA prescribing guidelines, April 2025. gov.uk
- NHS. Asthma. nhs.uk
- NHS. Asthma attack. nhs.uk
- Asthma + Lung UK. Asthma facts and statistics. asthma.org.uk
- NHS. Asthma: treatment. nhs.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.
