I have a terrible headache: what should I know?

A terrible headache needs attention to its pattern, associated symptoms and how suddenly it began. Many headaches improve with rest, fluids and a quiet environment, but a sudden or unusual headache can need urgent assessment.

Headache can occur with dehydration, heat exhaustion, a common cold, allergic rhinitis or chronic sinusitis. Viral illness such as COVID-19 may bring headache with fever, sore throat, cough or marked tiredness. Dengue fever can cause headache with fever, body aches, nausea or a rash, especially after mosquito exposure. Stress and generalised anxiety disorder can also contribute to head pain or muscle tension. These possibilities cannot be distinguished reliably from the pain alone.

Stop strenuous activity and rest somewhere cool and quiet. Sip water or an oral rehydration drink if you may have lost fluid through sweating, vomiting or diarrhoea. A cool cloth, gentle neck relaxation and reducing bright screens may help. Follow the label for any usual pain medicine and avoid taking more than directed. Record when the headache began, where it hurts, its severity, triggers and any fever or other symptoms.

Seek emergency care for a headache that reaches maximum intensity suddenly, follows a head injury, or comes with weakness, facial drooping, confusion, fainting, a seizure, trouble speaking, vision loss, a stiff neck or repeated vomiting. Get prompt medical advice for a new severe headache with fever, a rash, pregnancy, cancer, immune suppression or very high blood pressure. Arrange a clinical review if headaches keep returning, change pattern or are not settling.

Could this pattern fit migraine, infection, sinus symptoms or dehydration? Which pain medicines are suitable for me? What symptoms should make me seek urgent help? Should I keep a headache diary or have my eyes, blood pressure or neurological symptoms checked?