Chest Infection
Symptoms, Causes & Treatment
A chest infection is an infection of the lungs or airways, ranging from mild acute bronchitis to severe pneumonia requiring hospital admission. Prompt assessment ensures the right level of care.
What is a Chest Infection?
Chest infections encompass acute bronchitis (airway infection, usually viral) and pneumonia (lung tissue infection, bacterial or viral). Severity varies enormously — most chest infections in healthy adults are mild and self-limiting, while pneumonia in older adults or those with comorbidities can be life-threatening.
Symptoms of a Chest Infection
Symptoms vary depending on whether the infection involves the airways (bronchitis) or the lung tissue (pneumonia).
Productive cough with yellow or green sputum · Fever and chills · Chest pain worse on breathing (pleuritic) · Breathlessness · Fatigue and general malaise · Rapid breathing · Crackles on auscultation
Severe breathlessness with confusion or reduced consciousness · Rapidly worsening symptoms despite treatment · Coughing up blood · Very high fever with rigors · SpO2 below 93% · CURB-65 score 2 or more (high-risk pneumonia)
Severe breathlessness, SpO2 below 93%, confusion, cyanosis, or rapidly deteriorating symptoms — call 999 immediately.
What Causes Chest Infections?
Chest infections encompass a spectrum from mild self-limiting bronchitis to life-threatening pneumonia.
Community-acquired pneumonia (CAP) is the most common serious form of chest infection. It is caused by Streptococcus pneumoniae (most common), Haemophilus influenzae, atypical organisms (Mycoplasma, Legionella), and viral pathogens. CAP carries significant mortality in elderly patients.
Acute bronchitis is inflammation of the bronchi, almost always viral in origin. It is characterised by a productive cough, chest discomfort, and wheeze. Antibiotics are not routinely indicated as it resolves without treatment in most cases within 3 weeks.
COPD and asthma exacerbations are commonly precipitated by respiratory infections. Bacteria (H. influenzae, M. catarrhalis) and viruses (rhinovirus) are the main triggers. Treatment involves bronchodilators, antibiotics, and short-course steroids.
Aspiration pneumonia occurs when oropharyngeal secretions or gastric content enter the lungs. It is more common in the elderly, those with dysphagia, reduced consciousness, or significant GORD.
Hospital-acquired pneumonia develops 48+ hours after admission. It is caused by more resistant organisms including MRSA, Pseudomonas, and Gram-negatives. It has a higher mortality than community-acquired pneumonia.
Pneumococcal and influenza vaccination reduce the incidence of serious chest infections. Smoking cessation and optimal management of underlying lung disease (COPD, asthma) are essential preventive measures.
Key Risk Factors
Diagnosing a Chest Infection
Severity assessment using CURB-65 is the most important step in managing pneumonia, determining need for hospital admission.
Treatment for Chest Infections
Most acute bronchitis is viral and does not require antibiotics. Bacterial pneumonia requires antibiotics tailored to severity and risk factors.
Supportive Measures
Rest, stay hydrated, use paracetamol or ibuprofen for fever, inhale steam, and avoid smoking. Follow up if not improving after 48 hours of antibiotics.
Recurrent Chest Infections
Recurrent chest infections (3+ per year) should prompt investigation for underlying structural lung conditions or immune deficiency.
When to Seek Help
Severe breathlessness at rest, SpO2 below 93%, confusion, rapidly worsening symptoms, or coughing blood with high fever — call 999 immediately.
Breathlessness at rest, very high fever, confusion, or SpO2 below 95% requires same-day GP or A&E assessment.
Preventing Chest Infections
Many chest infections can be prevented through vaccination, smoking cessation, and good infection control practices.
Annual flu and one-off pneumococcal vaccines significantly reduce the risk of serious chest infections. All adults over 65 and those with chronic conditions should be vaccinated.
Smoking damages the mucociliary defence system, making the lungs vulnerable to infection. Stopping smoking is the single most effective measure for preventing recurrent chest infections.
Optimise management of COPD, asthma, heart failure, and diabetes, which all increase susceptibility to chest infections. Regular medication reviews and disease management reduce infective exacerbation risk.
Wash hands frequently with soap and water. Avoid touching the face. Stay away from people with respiratory infections when possible, particularly if elderly or immunocompromised.
A healthy diet rich in vitamins C and D, regular exercise, adequate sleep, and avoidance of excess alcohol all support immune function and reduce susceptibility to respiratory infections.
For those at aspiration risk (dysphagia, oesophageal reflux), head elevation at 30–45 degrees, thickened fluids, and speech and language therapy assessment significantly reduce aspiration pneumonia risk.
Getting Treatment
A GP can assess chest infection severity, prescribe antibiotics where appropriate, and decide if hospital admission is needed. An online GP consultation is suitable for mild chest infections.
Expert clinical advice, when you need it.
Chest Infection — Frequently Asked Questions
Antibiotics are only appropriate if bacterial infection is suspected — this applies to pneumonia or acute bacterial bronchitis with purulent sputum, fever, and chest signs. The vast majority of acute chest infections are viral and do not require antibiotics. A GP can assess and advise on whether antibiotics are needed.
Most bacterial chest infections start to improve within 48–72 hours of starting antibiotics. If you are not improving after 48 hours, or if you develop worsening breathlessness, confusion, or chest pain, seek urgent medical review. Complete the full antibiotic course even if you feel better.
Go to A&E if you have severe breathlessness at rest, cannot complete a sentence, become confused, develop cyanosis (blue lips), have SpO2 below 93%, or if your symptoms are rapidly worsening despite treatment. Call 999 if seriously unwell.
Pneumonia (infection of the lung tissue) is a more serious condition than bronchitis (infection of the airways). Pneumonia causes consolidation on chest X-ray, higher fever, and more severe breathlessness. Both may require antibiotic treatment, but pneumonia often requires hospital assessment.
Yes. Annual influenza and one-off pneumococcal vaccines significantly reduce the risk of serious chest infections. They are recommended for all adults over 65, those with COPD or asthma, immunocompromised individuals, and all healthcare workers.
Most chest infections are contagious during the early stages when viral shedding is highest. Stay home from work if feverish or feeling very unwell, cover coughs and sneezes, and wash hands frequently. Return to work when you have been fever-free for 24 hours and feel well enough.
Paracetamol or ibuprofen for fever and pain, steam inhalation or a humidifier, staying well hydrated, and getting adequate rest all support recovery. Avoid cough suppressants in productive cough, as clearing secretions is important.
Seek medical review if a chest infection is not improving after 3 weeks, if you are over 65 with any deterioration, if you are immunocompromised, or if symptoms recur. Recurrent chest infections may indicate an underlying structural lung problem requiring investigation.