Headache and post-nasal drip: what to know

Post-nasal drip is mucus moving from the back of the nose into the throat. Allergic rhinitis may cause clear drainage, sneezing, itching, and blocked nasal passages. A common cold can add sore throat, cough, tiredness, and a pressure-like headache. Chronic sinusitis may cause ongoing congestion, reduced smell, facial pressure, or thick drainage. Headache can also accompany dehydration, heat exhaustion, or a viral infection such as COVID-19. These symptoms overlap, so colour of mucus alone cannot establish the cause.

Dengue fever is a separate illness that can cause significant headache with fever, body aches, nausea, or a rash; travel, mosquito exposure, and fever history are useful details for a clinician.

Drink fluids regularly, rest, and use a saline nasal spray or rinse according to its instructions. Warm fluids may ease throat irritation. Avoid smoke and other nasal irritants, and wash hands if a cold or COVID-19 is possible. A pharmacist can advise on suitable pain relief or allergy treatment, taking account of pregnancy, blood pressure, other conditions, and current medicines. Do not start antibiotics simply because drainage is thick.

Get urgent help for a sudden severe headache, confusion, fainting, breathing difficulty, a stiff neck, new weakness, severe dehydration, or fever with a rapidly worsening illness. Arrange medical review for severe facial pain, swelling around the eye, persistent fever, repeated headaches, symptoms that keep returning, or nasal symptoms that do not settle. Seek prompt advice after mosquito exposure with fever, severe body pain, bleeding, or marked weakness.

Ask whether your pattern fits allergy, sinus inflammation, infection, or dehydration; whether testing is needed; and which nasal or pain treatments are appropriate with your health history. Mention recent travel, heat exposure, sick contacts, and every medicine you use.