Spring allergies usually occur when your immune system overreacts to an outdoor allergen, such as pollen. The most common allergens are pollen from wind-pollinated plants, such as trees, grasses, and weeds in the springtime. Pollen is the grains or tiny seeds of flowering plants, trees, and grasses. These seeds can be carried on the wind and can cause various symptoms, or none at all, in individuals who are exposed to them. For people with hay ...
