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Health condition · Clinically reviewed

Chest infection, from a lingering cough to pneumonia - and when it needs hospital.

Bronchitis, pneumonia, viral flares and exacerbations of chronic lung disease - the UK approach with CURB-65 scoring and BTS antibiotic guidance.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE, BTS and peer-reviewed sources you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK guidance on CURB-65, community-acquired pneumonia, atypicals and viral respiratory illness.

Key facts

Chest infection at a glance.

The essentials, in plain English - what a chest infection is, what causes it, how severity is scored and how it is treated in the UK.

  • What it is

    An umbrella term for lower respiratory tract infections - acute bronchitis, pneumonia, bronchiolitis in infants, and infective exacerbations of chronic lung disease.

  • Common causes

    Streptococcus pneumoniae leads bacterial CAP; viruses (influenza, COVID, RSV, parainfluenza) cause most bronchitis and bronchiolitis; atypicals include Mycoplasma, Chlamydia and Legionella.

  • Severity scoring

    CURB-65 (confusion, urea, respiratory rate, blood pressure, age) guides whether care is at home, on a ward, or in critical care.

  • First-line antibiotic

    Amoxicillin 500 mg three times daily for 5 days in mild community-acquired pneumonia; doxycycline or clarithromycin if penicillin-allergic.

  • Red flags

    Respiratory rate above 30, systolic BP under 90, SpO2 under 92%, new confusion, or two or more CURB-65 points - assess for hospital admission.

  • Prevention

    Annual influenza vaccine, pneumococcal vaccine, COVID boosters, RSV vaccine for eligible over-75s and smoking cessation cut the risk substantially.

Why this guide matters

A stepped, evidence-based approach.

Chest infections are common, mostly treatable and - with the right stratification - safely managed at home or in hospital. Three principles shape the rest of this page.

  • Score severity before antibiotics

    CURB-65 plus SpO2 tells you where care should happen. Not every cough with sputum needs antibiotics; not every pneumonia can stay at home.

  • Cover the likely organisms

    BTS-guided regimens balance pneumococcal cover in mild disease with atypical cover in severe disease and viral antivirals in season.

  • Vaccinate and treat the underlying

    Influenza, pneumococcal, COVID and RSV vaccines - plus good asthma, COPD and bronchiectasis control - prevent most preventable admissions.

How the diagnosis is made

From first cough to a clear plan.

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

  1. 01

    Assessing

    History and risk profile

    Cough, sputum, fever, breathlessness and pleuritic pain - plus smoking, occupation, travel, immunosuppression, hospitalisation and contacts.

  2. 02

    Assessing

    Examination and vitals

    Respiratory rate, oxygen saturation, blood pressure, temperature and heart rate. Auscultation for crackles, bronchial breathing and reduced air entry; percussion for dullness.

  3. 03

    Assessing

    CURB-65 severity score

    A five-point score that separates home care (0-1) from hospital assessment (2) and hospital admission (3 or more).

  4. 04

    Confirming

    Chest X-ray

    Looks for consolidation, pleural effusion, cavitation or bilateral change. The default imaging in suspected pneumonia.

  5. 05

    Confirming

    Bloods and microbiology

    FBC, CRP, U&Es, procalcitonin in selected cases, blood cultures if severe, sputum culture and AFB smear if TB is possible.

  6. 06

    Confirming

    Antigens and viral PCR

    Urinary pneumococcal and Legionella antigens in moderate-to-severe disease; PCR for influenza, COVID and RSV in season.

  7. 07

    Escalating

    ABG, CT and bronchoscopy

    Arterial blood gas for hypoxia; CT chest for complicated, non-resolving or immunocompromised cases; bronchoscopy with BAL when a specific pathogen must be found.

Typical timeline: assessed and started on treatment the same day, with review at 48 to 72 hours.

Symptoms

What a chest infection feels like.

Cough, fever and breathlessness dominate. The features below help decide whether it is bronchitis, pneumonia, a viral illness or something that needs urgent review.

  • Cough with purulent sputum

    Yellow or green sputum with a productive cough - the classic marker of a lower respiratory infection.

  • Fever and rigors

    A temperature above 38 degrees with sweats or shaking chills points to bacterial infection.

  • Breathlessness

    New or worsening breathlessness, especially at rest or on light activity, needs urgent assessment.

  • Pleuritic chest pain

    Sharp pain worse on deep breathing or coughing - often overlies an area of consolidation or a small effusion.

  • Haemoptysis

    Coughing up blood may accompany pneumonia, bronchiectasis flares or TB - always warrants review.

  • Crackles on auscultation

    Coarse crackles and bronchial breathing over one area suggest consolidation; widespread wheeze points to airway disease.

  • Confusion in older adults

    A drop in cognition in a person over 65 may be the only sign of pneumonia - it is a CURB-65 criterion in its own right.

  • Red flag - CURB-65 2 or more

    Respiratory rate above 30, BP under 90/60, SpO2 under 92%, urea above 7 or new confusion mean same-day hospital assessment.

Treatment

How chest infections are treated in the UK.

NICE and BTS regimens stratified by severity - from home-treated bronchitis and mild pneumonia to hospital combination therapy, TB and empyema care.

  • Mild CAP - oral amoxicillin

    CURB-65 0-1 treated at home with amoxicillin 500 mg three times daily for 5 days; doxycycline or clarithromycin if penicillin-allergic.

  • Moderate CAP - hospital review

    CURB-65 2 usually needs a hospital assessment with oral or IV combination therapy per BTS guidance.

  • Severe CAP - IV combination

    CURB-65 3 or more: IV co-amoxiclav plus clarithromycin, or benzylpenicillin plus doxycycline; escalate to HDU or ITU if failing.

  • AECOPD and asthma flares

    Amoxicillin or doxycycline, oral steroids, nebulised bronchodilators, controlled oxygen and NIV where indicated.

  • Influenza and COVID

    Oseltamivir within 48 hours for at-risk influenza; dexamethasone plus tocilizumab, remdesivir or oral antivirals for COVID per NICE.

  • Tuberculosis

    Six-plus months of RIPE (rifampicin, isoniazid, pyrazinamide, ethambutol) under a specialist TB service - a notifiable disease.

  • Empyema and abscess

    Chest drain, intrapleural urokinase and surgical decortication for empyema; prolonged antibiotics and drainage for lung abscess.

  • Prevention and supportive care

    Annual flu, pneumococcal, COVID and RSV vaccines, smoking cessation, fluids, paracetamol and clear safety-netting advice.

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 hospital team knows your history and can tell you which parts apply to you. If in doubt, get seen the same day.

  • NICE. Pneumonia in adults: diagnosis and management (CG191) and NG138 (antimicrobial prescribing).

  • British Thoracic Society (BTS). Guidelines for the management of community-acquired pneumonia in adults (2015 update).

  • NICE. COPD exacerbations and asthma exacerbations - antimicrobial prescribing (NG114, NG117).

  • UK Health Security Agency. Guidance on tuberculosis, influenza, RSV and COVID-19.

Red flags

When a chest infection needs urgent care.

Most chest infections are managed safely in primary care. These are the features that mean same-day hospital assessment or specialist input.

  • CURB-65 of 2 or more

    Confusion, urea above 7, respiratory rate over 30, BP under 90/60 or age 65 and over - two or more points triggers hospital assessment.

  • SpO2 under 92 percent

    Hypoxia on air is a red flag - needs urgent oxygen assessment and ABG in secondary care.

  • Sepsis features

    NEWS2 of 5 or more, mottled skin, oliguria or a lactate above 2 - treat as sepsis with the Sepsis Six within an hour.

  • Massive haemoptysis

    More than 100 ml of blood in 24 hours or brisk fresh bleeding - a respiratory emergency needing airway protection.

  • Empyema or complex effusion

    Persistent fever, rising CRP or a loculated effusion after 48 hours of antibiotics - needs chest drain and specialist review.

  • Non-resolving pneumonia

    Symptoms or X-ray changes that persist beyond 6 weeks despite treatment - warrants CT and consideration of malignancy or TB.

  • Suspected tuberculosis

    Weight loss, night sweats, cough over 3 weeks, contacts or high-risk background - AFB smear, culture and specialist TB referral.

  • Immunocompromised host

    Chemotherapy, transplant, HIV or high-dose steroids - broaden thinking to PCP, fungal and opportunistic infection early.

  • Bronchiolitis in an unwell infant

    Poor feeding, apnoea, marked recession or SpO2 under 92 percent - paediatric assessment on the same day.

Living with it

Recovering well, and staying well.

Four things that make the biggest difference after a chest infection - realistic expectations on recovery, up-to-date vaccines, stopping smoking and a clear safety net.

A quiet reminder

Cough can outlast the infection.

A post-infective cough that lasts three to eight weeks is common and does not on its own mean antibiotics have failed - it means the airway is settling.

  1. 01 Recovery

    Give it time

    Cough and tiredness can last several weeks after a chest infection - it does not mean the antibiotics have failed.

  2. 02 Vaccines

    Get the free jabs

    Annual influenza, pneumococcal, COVID boosters and (from 75) RSV cut the risk of a serious chest infection sharply.

  3. 03 Smoking

    Stopping helps fast

    Cilia recover within weeks of stopping smoking - the single biggest thing you can do for your lungs.

  4. 04 Escalate

    Know your safety net

    Return the same day if breathing gets worse, fevers return, you cough up blood, or you feel confused or drowsy.

Frequently asked

Everything we get asked about chest infections.

Quick answers on bronchitis versus pneumonia, when antibiotics help, when to seek admission and how to prevent the next one.

  • What is a chest infection?

    An infection of the lower airways or lung tissue. It ranges from acute bronchitis (an airway infection, usually viral) to pneumonia (infection of the lung tissue itself), plus bronchiolitis in infants and infective flares of COPD, asthma and bronchiectasis.

  • How do I know if it is bronchitis or pneumonia?

    Bronchitis usually gives a productive cough with mild fever and normal oxygen levels and does not need antibiotics in most healthy adults. Pneumonia adds features like breathlessness, high fever, pleuritic chest pain, low oxygen or crackles and consolidation on a chest X-ray. If you feel very unwell, breathless or hypoxic, seek same-day review.

  • Do I always need antibiotics?

    No. Most acute bronchitis and viral infections settle without antibiotics. Antibiotics are given when bacterial pneumonia is likely, when an exacerbation of COPD is bacterial, or when CURB-65 and clinical judgement suggest bacterial infection. Amoxicillin 500 mg three times daily for 5 days is the usual first-line choice in mild community-acquired pneumonia.

  • When should I be admitted to hospital?

    When CURB-65 is 2 or more, or when SpO2 is under 92 percent, respiratory rate is over 30, systolic BP is under 90, you are newly confused, or you have sepsis features. Older adults, pregnant patients and immunocompromised people have a lower threshold for admission.

  • What about influenza, COVID and RSV?

    Viral chest infections are common, especially in winter. Oseltamivir helps in flu if started within 48 hours in high-risk groups. Dexamethasone and antivirals like remdesivir or oral options are used in COVID pneumonia per NICE. RSV is the leading cause of bronchiolitis in infants and is now vaccine-preventable in eligible older adults.

  • How can I prevent chest infections?

    Have the annual flu jab, pneumococcal vaccine, COVID boosters and (if eligible) the RSV vaccine. Stop smoking, get treatment for underlying asthma, COPD or bronchiectasis, and see your GP early if a cough or breathlessness is not settling.

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