If your symptoms happen every so often in spring, summer, or early fall, you may have seasonal allergies. Tree pollen is a problem in spring, grass pollen in late spring and summer, and weeds in fall.
If you have symptoms year-round, you may be allergic to dust mites, pet dander, or mold and mildew. Mold spores can also be a problem outdoors, usually when weather is warm and humid.
It’s possible to have both kinds of allergies. Your allergist can help you figure out more exactly what you’re allergic to.