Persistent headache with fever: what to know

Fever and headache often occur with infections such as a respiratory illness, but the combination can also reflect dehydration or another inflammatory problem. A stiff neck, light sensitivity, new rash, drowsiness, confusion, or repeated vomiting raises concern for an illness affecting the nervous system and should not be watched at home.

Brain tumours do not usually cause fever by themselves, and headache with fever does not mean a brain tumour. Brain metastases or glioblastoma may cause headache in people with those conditions, while fever may have a separate cause or relate to treatment. The clinical context matters.

Contact a clinician promptly and describe the temperature, when the headache began, recent infections, travel, new medicines, immune problems, and any cancer treatment. Rest, take fluids in small amounts, and use fever medicine only if it is safe for you and used according to instructions. Avoid sharing medicines and do not delay assessment to see whether a remedy works.

Seek emergency help immediately for confusion, extreme sleepiness, a seizure, fainting, weakness, trouble speaking, a stiff neck, a new purple or non-blanching rash, breathing difficulty, severe dehydration, persistent vomiting, or rapidly worsening headache. People receiving chemotherapy or other immune-suppressing treatment should use their oncology team’s fever instructions without delay.

Ask whether you need examination, testing, or treatment for infection; which fever medicine is suitable; how often to check your temperature; and which changes require emergency care. If you are on cancer treatment, ask which contact number to use outside clinic hours.