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RespiratoryGlobal

Pneumonia

Pneumonia is an infection that inflames the tissue in one or both lungs, usually caused by bacteria or viruses. It causes a cough, fever, and difficulty breathing. While many people recover well with treatment, pneumonia can be serious, especially in young children, older adults and those with other conditions.

Written byAikins Apreku
Reviewed byDeborah Adotso, General Nurse
Updated June 2026

Quick Facts

What it is
An infection inflaming the lung tissue
Common causes
Bacteria or viruses
Key symptoms
Cough, fever, breathlessness, chest pain
Can be serious
Especially in higher-risk groups
Treatment
Depends on cause; bacterial needs antibiotics

What is pneumonia?

Pneumonia is an infection that causes inflammation in the lungs, specifically the tiny air sacs (alveoli) where oxygen passes into the blood. When these become inflamed and fill with fluid or pus due to infection, it becomes harder for the lungs to do their job, leading to symptoms like coughing, fever and difficulty breathing. Pneumonia can affect one or both lungs and ranges from mild to severe.

Unlike bronchitis, which affects the airways, pneumonia affects the lung tissue itself, which is part of why it can be more serious. It is usually caused by a bacterial or viral infection. While many otherwise healthy people recover well with appropriate treatment, pneumonia is a significant illness that can be serious, particularly in young children, older adults, and people with other health conditions or weakened immune systems, who are more vulnerable to complications.

Symptoms

Pneumonia symptoms can develop quickly or more gradually, and can range from mild to severe. They often resemble a bad chest infection. Common symptoms include:

  • •A cough, which may bring up mucus or phlegm
  • •Difficulty breathing or breathlessness, even at rest in more severe cases
  • •A high temperature, sweating and shivering
  • •Chest pain, often worse when breathing or coughing
  • •A rapid heartbeat and rapid breathing
  • •Feeling generally unwell, tired, and loss of appetite
  • •In older adults, sometimes confusion, and symptoms can be less obvious

Causes and risk factors

Pneumonia is usually caused by an infection that reaches the lungs, with bacteria and viruses being the most common culprits. It can develop on its own or sometimes follow another respiratory infection like a cold or flu. Several factors increase the risk of getting pneumonia or of it being more serious:

  • •Bacterial infections (a common cause, often treatable with antibiotics)
  • •Viral infections, including those that cause colds, flu and COVID-19
  • •Being very young or older
  • •Smoking, which damages the lungs' defences
  • •Existing heart or lung conditions, such as asthma or COPD
  • •A weakened immune system, or other long-term health conditions

Treatment and recovery

Treatment for pneumonia depends on its cause and severity. Bacterial pneumonia is treated with antibiotics, and it is important to complete the full course. Many people with milder pneumonia can be treated at home with antibiotics (if bacterial), rest, plenty of fluids, and painkillers for fever and discomfort. Viral pneumonia is managed supportively, as antibiotics do not work against viruses, though it still needs medical assessment.

More severe pneumonia, or pneumonia in higher-risk people, may need hospital treatment, where oxygen, fluids and other support can be given. Recovery from pneumonia takes time — many people feel better within a week or two of starting treatment, but tiredness and a cough can linger for several weeks or longer as the lungs heal fully. It is important to seek medical assessment for suspected pneumonia rather than self-treating, as a doctor can determine the cause, prescribe appropriate treatment, and judge whether home or hospital care is needed.

Higher-risk groups, prevention and emergencies

Pneumonia can affect anyone, but it is more likely to be serious in certain groups: babies and young children, older adults, smokers, pregnant women, and people with existing heart or lung conditions, diabetes, or weakened immune systems. For these groups, any signs of a chest infection or pneumonia warrant prompt medical attention, as early treatment improves the outcome and reduces the risk of complications.

Some pneumonia can be prevented. Vaccines are available against some of the common causes of pneumonia and against flu (which can lead to pneumonia), and are recommended particularly for higher-risk groups, so it is worth asking a doctor about eligibility. Not smoking, good hygiene to reduce respiratory infections, and managing underlying health conditions well all help reduce the risk.

Pneumonia can become an emergency, so it is vital to recognise the warning signs. Severe difficulty breathing, breathlessness at rest, blue lips or face, chest pain, coughing up blood, confusion (especially in older adults), or a very rapid heartbeat all need urgent medical attention. Because pneumonia affects the lungs directly and can deteriorate, it should always be taken seriously, and prompt medical care sought when it is suspected — especially for anyone in a higher-risk group.

When to see a doctor

  • •If you suspect pneumonia — a cough with fever, breathlessness and chest pain — seek medical assessment, as it needs proper diagnosis and treatment
  • •Seek urgent or emergency help for severe difficulty breathing, breathlessness at rest, blue lips or face, chest pain, or coughing up blood
  • •If there is confusion or unusual drowsiness, especially in an older adult — seek urgent care
  • •If you are in a higher-risk group and develop chest infection symptoms — seek advice promptly
  • •If symptoms are severe, rapidly worsening, or a chest infection is not improving
  • •For a baby or young child with breathing difficulty, a high fever, or who seems very unwell — seek urgent help

Frequently Asked Questions

Pneumonia symptoms include a cough (often with mucus), difficulty breathing or breathlessness, a high temperature with sweating and shivering, chest pain that is worse when breathing or coughing, rapid heartbeat and breathing, tiredness and loss of appetite. In older adults it can cause confusion and be less obvious. Suspected pneumonia needs medical assessment.

Sources & References

  1. 1.NHS. Pneumonia.
  2. 2.American Lung Association. Pneumonia.
  3. 3.World Health Organization. Pneumonia.

LifeCheckIQ content is based on peer-reviewed research, recognised clinical guidelines, and authoritative medical sources, and is reviewed by Deborah Adotso, General Nurse, for clinical accuracy.

Related

Bronchitis →Cough →Fever →Cold and Flu →

Medical Disclaimer: This tool is for informational and educational purposes only. Results are not a medical diagnosis. Always consult a qualified healthcare professional for medical advice, diagnosis, or treatment. In an emergency, call your local emergency number or visit the nearest hospital immediately.