Dehydration and fever: what to know

A fever raises the body's demand for fluid, and sweating, rapid breathing, vomiting or diarrhoea can add to the loss. Dehydration may cause thirst, dry mouth, headache, dizziness, tiredness and darker urine. It does not identify the cause of a fever: infections such as gastroenteritis or a urinary tract infection are possible explanations, among others. The height and duration of a temperature, your age, and other symptoms all affect how urgently you need advice.

Rest and take frequent small sips of water or an appropriate oral rehydration solution. If nausea is present, try small amounts more often rather than a large drink. Continue suitable food when you can tolerate it. Keep the room comfortable and wear light clothing; avoid extreme cooling. Follow the label or a clinician's advice for any fever medicine, especially if you have kidney, liver or stomach problems or take regular medicines.

Get urgent help for confusion, fainting, a seizure, severe breathing difficulty, a stiff neck, a new widespread rash, severe weakness or inability to keep fluids down. Seek prompt medical advice for a persistent or worsening fever, very little urine, severe abdominal or back pain, or blood in vomit, stool or urine. Babies, older adults, pregnant people and those with long-term conditions may need earlier assessment.

Ask which rehydration drink is suitable, how to monitor urine and temperature, and whether your symptoms suggest an infection needing examination.