Why does pneumonia cause fever?

When infection affects the lungs, immune cells release chemical signals that act on the brain's temperature regulation centre. The body then conserves or produces heat, which may cause feeling cold, shivering, sweating, headache, and tiredness as the temperature changes. Fever is a very common presentation of Pneumonia. Fever has many possible causes, however, and the combination of symptoms, examination, and clinical history helps identify what is happening.

Rest, wear light comfortable clothing, and drink fluids regularly if safe for you. Monitor how you feel as well as the temperature: worsening breathlessness, chest pain, confusion, or inability to drink are more concerning than a reading alone. Arrange prompt medical advice for suspected pneumonia. A clinician can check your breathing, consider other causes, and tell you whether treatment or further tests are needed. Use fever medicines only according to their label or personalised medical advice.

Seek urgent medical help for severe shortness of breath, blue or grey lips, confusion, fainting, severe chest pain, a stiff neck with severe illness, or a rapidly worsening condition. Get same-day advice for fever with a cough and increasing weakness or breathing difficulty. Infants, older adults, pregnant people, and people with chronic conditions or reduced immunity should be assessed early when they develop fever and chest symptoms.

Ask what is likely causing the fever, whether your lungs and oxygen level need checking, which home measures are safe with your other medicines, and what symptoms should prompt urgent reassessment.