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Symptom hub

Breathing problems, from red-flag stridor to chronic breathlessness.

A symptom, not a diagnosis. This guide maps the common causes, the emergencies you should never miss and how UK teams work out what is really going on.

A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Editorial team

    Written by our editorial team from the UK sources listed on each page.

  • 02

    Sourced from guidance

    Checked against NICE, BTS, GINA, GOLD and ERS statements you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including biologics for severe asthma, GOLD 2026 for COPD and 2WW lung-cancer pathways.

Key facts

Breathing problems at a glance.

The essentials, in plain English. Ten broad categories, one symptom hub and the red-flag features that change the tempo.

  • What it is

    A symptom, not a diagnosis. Breathlessness, wheeze, stridor, cough or haemoptysis can arise from lungs, heart, blood or the breathing pattern itself.

  • Acute vs chronic

    Acute breathlessness (minutes to hours) can signal PE, pneumothorax, MI, heart failure, asthma attack or anaphylaxis. Chronic points to asthma, COPD, ILD, heart failure or deconditioning.

  • Red-flag pattern

    Stridor, one-word sentences, SpO2 below 92%, RR above 30, tripod posture or reduced consciousness need same-day emergency assessment.

  • Haemoptysis

    In any adult over 40 with unexplained coughing of blood, a 2WW suspected lung-cancer referral is warranted.

  • Foundation workup

    History, examination, oxygen saturations, CXR, ECG and spirometry answer most questions. CTPA, HRCT, echo and sleep study follow when indicated.

Why this guide matters

One symptom, many diagnoses.

Breathing problems are the top three reasons people call 111, visit their GP or attend A&E. Sorting emergencies from chronic conditions is the whole game.

  • Split acute from chronic first

    Sudden breathlessness within minutes or hours points to PE, pneumothorax, MI, asthma, anaphylaxis or heart failure. Gradual onset points to COPD, ILD, deconditioning or anaemia.

  • Match the noise to the level

    Stridor means upper airway; wheeze means lower airway; crackles suggest fluid or fibrosis; a normal chest with breathlessness can still be PE or dysfunctional breathing.

  • Never ignore blood in the sputum

    Adults over 40 with unexplained haemoptysis need a 2WW suspected lung-cancer referral. Massive haemoptysis is an airway emergency.

How the diagnosis is made

From first breath to a clear plan.

The steps a UK GP or respiratory team will normally follow, in order, so you know what to expect and why.

  1. 01

    Assessing

    ABC and severity check

    Rapid vitals: SpO2, respiratory rate, blood pressure, level of consciousness, ability to speak in sentences and use of accessory muscles.

  2. 02

    Assessing

    History and timeline

    Onset, duration, triggers, orthopnoea, PND, wheeze, cough, sputum, haemoptysis, chest pain, smoking, occupation, travel and medications.

  3. 03

    Assessing

    Focused examination

    Auscultation, chest expansion, trachea, JVP, oedema, calf swelling and cardiac exam to separate lung, heart and vascular causes.

  4. 04

    Confirming

    Urgent bedside tests

    CXR, ECG, FBC, U&Es, D-dimer where PE possible, troponin, BNP, ABG and peak flow to rule in or out the common serious causes.

  5. 05

    Confirming

    Spirometry and FeNO

    Spirometry with reversibility for airflow obstruction; FeNO and peak flow diary help confirm asthma and its control.

  6. 06

    Specialist

    Cross-sectional imaging

    CTPA for suspected PE, HRCT for interstitial lung disease and standard CT chest for masses, effusions or bronchiectasis.

  7. 07

    Specialist

    Echo, sleep study and full PFTs

    Echocardiogram for cardiac causes, overnight oximetry or sleep study for OSA and full lung volumes with DLCO for ILD and severe asthma.

Typical timeline: an emergency answer in hours, a chronic answer in weeks.

Symptoms

What breathing problems look like.

Breathlessness, wheeze, stridor, cough, haemoptysis and pleuritic pain - each pattern points to a shortlist of causes.

  • Breathlessness

    At rest, on exertion or lying flat (orthopnoea). Sudden onset raises PE, pneumothorax, MI or anaphylaxis.

  • Wheeze

    Musical expiratory noise, classic for asthma and COPD. Fixed monophonic wheeze can mean foreign body or tumour.

  • Stridor

    Harsh inspiratory noise from upper-airway obstruction. Always a red flag needing same-day airway assessment.

  • Cough

    Acute (under 3 weeks) usually infective; chronic (over 8 weeks) suggests asthma, reflux, upper-airway drip or ACE-inhibitor use.

  • Haemoptysis

    Coughing blood. Consider infection, PE, bronchiectasis, vasculitis and lung cancer. Adults over 40 with unexplained blood need 2WW.

  • Pleuritic chest pain

    Sharp pain worse on inspiration. Think PE, pneumonia, pneumothorax and pleural effusion.

  • Snoring and daytime sleepiness

    Loud snoring, witnessed apnoeas and morning headaches point to obstructive sleep apnoea.

  • Red flag - critical airway signs

    One-word sentences, tripod posture, silent chest, cyanosis, drowsiness or SpO2 below 92% mean call 999.

Treatment

How breathing problems are treated.

Treat the cause. Oxygen and NIV in the acute setting; inhalers, biologics, cardiac therapy, CPAP and pulmonary rehab for the chronic ones.

  • Oxygen therapy

    Titrated to SpO2 94-98% (88-92% if type 2 respiratory failure risk). NIV / BiPAP for hypercapnic failure, CPAP for cardiogenic pulmonary oedema and OSA.

  • Inhaled therapy

    SABA, LABA, LAMA and inhaled corticosteroids in single or triple combinations, matched to asthma or COPD phenotype and severity.

  • Asthma biologics

    Dupilumab, omalizumab, mepolizumab, benralizumab and tezepelumab for severe eosinophilic or allergic asthma (see /treatments/asthma-biologics-clinic/).

  • COPD optimisation

    Bronchodilators, inhaled steroids where indicated, long-term oxygen if hypoxaemic, plus pulmonary rehabilitation and smoking cessation.

  • Heart-failure therapy

    ACE inhibitor or ARB, beta-blocker, MRA, SGLT2 inhibitor, ARNI, diuretics and, in selected patients, ICD or CRT devices.

  • PE and anticoagulation

    Anticoagulation (DOAC or LMWH) for confirmed PE; thrombolysis reserved for haemodynamic instability.

  • Pulmonary rehabilitation

    MDT programme of exercise, education and breathing training for COPD, ILD, post-COVID and any chronic breathlessness (see /treatments/pulmonary-rehabilitation-programme/).

  • Breathing retraining and CPAP

    Physio-led retraining for hyperventilation and dysfunctional breathing. CPAP or MAD (with weight loss and surgery where indicated) for OSA.

What this guide is based on

The sources behind every claim on this page.

UK national guidance and specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or respiratory specialist knows your history and tests and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Asthma: diagnosis, monitoring and chronic asthma management (NG245) and BTS/SIGN joint guideline.

  • NICE. Chronic obstructive pulmonary disease in over 16s (NG115) and GOLD 2026 report.

  • NICE. Suspected cancer: recognition and referral (NG12) - 2WW pathway for lung cancer.

  • British Thoracic Society. Emergency oxygen use in adult patients and pulmonary rehabilitation guidelines.

  • European Respiratory Society. Guidelines on chronic cough, ILD, PAH and dysfunctional breathing.

Red flags

When breathing problems need urgent attention.

Most respiratory symptoms are manageable in primary care. These are the situations that are not, and where the tempo changes to hours.

  • Stridor

    Inspiratory noise from the upper airway. Consider anaphylaxis, epiglottitis, foreign body or tumour. Call 999.

  • Silent chest and one-word sentences

    Life-threatening asthma or severe COPD exacerbation. Needs immediate hospital treatment.

  • Sudden pleuritic pain and breathlessness

    Consider pulmonary embolism or pneumothorax. Same-day imaging and urgent review.

  • Massive haemoptysis

    Coughing large volumes of blood is an emergency. Airway protection and urgent bronchoscopy or interventional radiology.

  • Unexplained haemoptysis over 40

    Two-week-wait suspected lung-cancer referral, with CXR and CT chest as indicated.

  • Type 2 respiratory failure

    Rising CO2 with acidosis needs NIV / BiPAP and specialist input. Target SpO2 88-92% in at-risk patients.

  • Anaphylaxis

    Rapid airway swelling, wheeze, rash and hypotension. IM adrenaline first, then transfer.

  • Cardiac chest pain with breathlessness

    Consider acute coronary syndrome or acute heart failure. ECG, troponin and cardiology review.

  • New oxygen requirement

    Any adult newly needing oxygen deserves urgent secondary-care assessment, whatever the suspected cause.

Living with it

Treatable symptoms, with a clear plan.

Four things that make the biggest difference day to day: pacing, keeping active, inhaler technique and a written action plan.

A quiet reminder

Vaccinate, stop smoking, keep moving.

Influenza, pneumococcal, COVID and RSV vaccines, smoking cessation and regular activity outperform almost every other lifestyle change for the lungs.

  1. 01 Pace

    Pace and plan

    Break tasks into smaller steps, sit to do jobs where you can, and rest before you need to.

  2. 02 Move

    Keep moving

    Breathlessness is not harmful in itself. Pulmonary rehab and regular walking make daily life easier over months, not days.

  3. 03 Inhalers

    Use inhalers properly

    Technique matters more than brand. Ask your pharmacist or nurse for a check, and use a spacer with metered-dose inhalers.

  4. 04 Escalate

    Have an action plan

    Know your normal, your warning signs and who to call. A written plan for asthma or COPD saves attendances and lives.

Frequently asked

Everything we get asked about breathing problems.

Quick answers on emergencies, common tests, asthma vs COPD and breathing retraining.

  • What causes sudden shortness of breath?

    Acute breathlessness can come from pulmonary embolism, pneumothorax, an asthma or COPD attack, heart failure, myocardial infarction, pneumonia, anaphylaxis or a panic attack. Sudden onset with chest pain, low oxygen saturations or collapse is an emergency and needs 999.

  • When is breathlessness an emergency?

    Call 999 or go to A&E for stridor, one-word sentences, tripod posture, cyanosis, drowsiness, SpO2 below 92% or breathing rate above 30. Chest pain, coughing blood or a first episode of severe breathlessness also warrant urgent assessment.

  • What tests will I have for breathing problems?

    Most people start with vitals, a chest X-ray, ECG and blood tests, followed by spirometry with reversibility, FeNO and a peak flow diary. Further tests such as CTPA, HRCT, echocardiogram, full lung-function testing or a sleep study are added when the initial workup points to a specific diagnosis.

  • Is coughing up blood always serious?

    A small streak with a viral cough is usually benign, but any adult over 40 with unexplained haemoptysis needs a two-week-wait referral for suspected lung cancer. Larger volumes, recurrent episodes or associated weight loss should be seen the same day.

  • What is the difference between asthma and COPD?

    Asthma is typically variable, reversible airflow obstruction that starts in childhood or young adulthood and responds well to inhaled corticosteroids and biologics. COPD is largely fixed airflow obstruction, usually in older adults with a smoking history, treated with bronchodilators, pulmonary rehab and, in some, inhaled steroids.

  • Can breathing retraining really help?

    Yes. Dysfunctional breathing and hyperventilation are common, under-diagnosed causes of breathlessness. Specialist physiotherapy, breathing pattern retraining and, where anxiety plays a part, CBT can dramatically improve symptoms even when lung tests are normal.

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