A headache accompanied by a stuffy nose or post-nasal drip, or one that starts with changes in the weather, is often believed to be a sinus headache. However, a report at the 2001 meeting of the American Academy of Neurology found that, when evaluated, most people turned out to have another cause for their headaches. Migraine was the most common overlooked cause. Migraines should be considered as a possibility whenever there are recurrent headaches that affect daily activity. Knowing the right cause is important to getting the right treatment. Migraines are frequently missed in children.