10 Signs You Could Have Allergies
1. Headaches

It's been reported that up to 15 percent of Americans who suffer from allergies also develop headaches as a common symptom. In most cases, these headaches are triggered by swelling. When the nasal passages become obstructed, this can increase skull pressure, leading to headaches.
You may experience increased pressure in your forehead, behind your eyes, along your cheeks, or even within your teeth. In more severe cases, individuals suffer from allergy-related migraines. Researchers believe this may be due to swelling of blood vessels in your head.