A headache appears out of nowhere. Your throat feels strange. You notice a rash that definitely was not there yesterday. For many people, the first response is no longer to reach for the phone and call a doctor. It is to open a search engine. Looking up symptoms can sometimes provide useful general information, particularly when you are deciding how closely to monitor a minor problem. The trouble starts when online research becomes a substitute for medical advice. Search results cannot examine you, ask detailed follow-up questions, or understand your full medical history. Knowing when to close the browser and speak to a healthcare professional can save you unnecessary worry…