Specifically, it’s the protein released by plants that causes the sinuses, which are small air-filled cavities behind your cheekbones and forehead, to become swollen, irritated, and inflamed.
If you are experiencing symptoms of hay fever already, you likely suffer from an allergy to tree pollen, which is released during spring.
Symptoms ongoing, or triggered, at the beginning of summer (June) is likely caused by an allergic reaction to grass pollen.
In late autumn, hay fever symptoms could be representative of a weed pollen allergy.