What causes a constant headache?

Tight neck and scalp muscles, poor sleep, stress, missed meals, eye strain, or frequent pain-medicine use can maintain headache. Dehydration and Heat Exhaustion may cause headache with thirst, weakness, dizziness, or nausea. Allergic Rhinitis and Chronic Sinusitis can produce facial pressure and blocked or runny nose, while a Common Cold or COVID-19 may bring headache with fever, sore throat, cough, or body aches. Dengue Fever is another consideration in a person with fever, marked aches, rash, or recent exposure in an affected area. Generalised Anxiety Disorder can amplify muscle tension and pain, but a new persistent headache still deserves a clinical history.

Drink fluids, eat regularly, rest from screens, use a quiet room, and record timing, location, severity, associated symptoms, and medicines taken. Arrange an appointment if the headache continues, changes pattern, recurs often, or interferes with work or sleep. A clinician may check blood pressure, vision, neurological function, hydration, medication use, and signs of infection before deciding whether tests are needed.

Seek emergency care for a sudden severe headache, weakness or numbness on one side, confusion, fainting, seizure, new speech or vision difficulty, stiff neck with fever, repeated vomiting, a headache after head injury, or a new headache during pregnancy or soon after delivery. Urgent assessment is also needed when fever and severe illness are worsening.

Ask what headache pattern you have, whether a medicine or illness may be sustaining it, which warning signs matter for you, and whether an examination or investigation is appropriate.