Flu and fever: what to know

Fever is a raised body temperature caused by the immune response. With flu it may occur alongside chills, sweats, headache, aching muscles, marked tiredness, sore throat and cough. A cold can cause similar upper-airway symptoms but often feels less sudden. Fever can also occur with acute bronchitis, COVID-19, pneumonia and other infections, so it does not identify flu on its own.

The direction of illness helps: improvement followed by renewed fever, worsening cough, chest pain, or increasing breathlessness may suggest a complication and deserves medical review.

Rest, drink small amounts often, wear light comfortable clothing, and keep the room suitably cool without becoming chilled. A thermometer can help you follow the trend, but how you feel and whether you can drink are also useful clues. Use fever or pain medicine according to the label and ask a pharmacist about child dosing, pregnancy, liver disease, kidney disease or interactions. Avoid cold baths and do not give aspirin to children.

Seek emergency help for severe breathing difficulty, blue lips, confusion, a seizure, collapse, a stiff neck with severe headache, or inability to wake normally. Arrange prompt care for dehydration, persistent vomiting, severe localised pain, a new rash with serious illness, or fever that returns after improvement. Babies, older adults, pregnant people and those with weakened immunity may need earlier advice.

Ask whether the pattern fits flu or another infection, whether testing is useful, how to use fever medicine safely, and which changes should lead to an urgent reassessment.