Hay Fever
What causes it?
Hay fever is an allergic reaction to pollen and sometimes, fungal spores.
Plants and pollen
Grass pollen is the most common cause of hay fever, followed by trees and weeds, then flowers. You can be allergic to one, some or many different types of plants but because they all release pollen at different times of the year, you probably won't suffer for the whole season. Phew!