What should you know about half headache?

One-sided pain may occur with migraine, neck or jaw tension, blocked nasal passages, or an infection. A [Common Cold](/conditions/common-cold/) or [Allergic Rhinitis](/conditions/allergic-rhinitis/) may cause pressure around the face. [Chronic Sinusitis](/conditions/chronic-sinusitis/) can produce ongoing facial pressure, though not every one-sided headache comes from the sinuses. Heat, missed meals, poor sleep, and [Dehydration](/conditions/dehydration/) can also contribute.

The timing, severity, triggers, associated symptoms, and examination matter more than which side hurts. Fever, a rash, recent travel, mosquito exposure, or respiratory symptoms may point toward an illness such as [Dengue Fever](/conditions/dengue-fever/) or [COVID-19](/conditions/covid-19/).

Rest in a quiet, dim room, drink fluids, eat if you have missed a meal, and use a cool or warm compress according to what feels helpful. Keep a record of onset, duration, triggers, medicines, sleep, and associated symptoms. Use pain medicine only as directed on its label or by a clinician; frequent use can itself contribute to recurring headaches. Heat exposure with heavy sweating may require attention to [Heat Exhaustion](/conditions/heat-exhaustion/).

Call emergency services for a sudden explosive headache, weakness or numbness on one side, trouble speaking, confusion, seizure, fainting, new vision loss, or a stiff neck with fever. Seek prompt review for a new persistent pattern, headache after head injury, repeated vomiting, pregnancy-related headache, or headache with a widespread rash. Anxiety can amplify pain, but a new neurological symptom should not be attributed to [Generalised Anxiety Disorder](/conditions/generalised-anxiety-disorder/) without assessment.

Ask whether the pattern fits migraine, tension, sinus symptoms, dehydration, or another cause; which pain reliever is suitable; and whether an examination or further testing is needed. Bring your headache diary and a list of medicines.