[gallery ids="330781"] Seasonal allergies can be caused by small particles of dust, pollen, mold or other allergens entering the body as it breathes. Allergy symptoms and causes can vary, so it is important to know which symptoms to watch for, what a person is allergic to and which medicines can help ease a person's symptoms. Use this guide to learn more about common North Texas allergens, symptoms and over-the-counter treatment options.