Severe headache with flu: what to know

Flu often causes a headache alongside fever, chills, aching muscles, cough, and marked tiredness. Fever and sweating can reduce fluid levels, while blocked sinuses may add pressure around the face and forehead. A headache is a flu symptom, but it is not specific to flu; COVID-19, a common cold, sinus disease, and other illnesses can overlap. Testing and an examination may be needed when the diagnosis is uncertain.

Rest, drink fluids regularly, and keep the room comfortably cool. Follow the label for any pain or fever medicine, and check with a pharmacist if you take other medicines, have liver or kidney disease, are pregnant, or are treating a child. Avoid doubling products that contain the same pain-relieving ingredient. Stay home while unwell and limit close contact with people at higher risk.

Get emergency help for a severe headache with a stiff neck, confusion, fainting, seizure, new weakness, trouble speaking, breathing difficulty, chest pain, or repeated vomiting. Seek prompt medical advice if fever persists, fluids cannot be kept down, urine becomes very infrequent, or symptoms worsen after seeming to improve. People with pregnancy, advanced age, or significant long-term conditions should seek advice early.

Ask whether flu testing is useful, whether antiviral treatment is appropriate for your situation, how much fluid to take, and which changes mean you should return urgently.