Pollen is one of the most common triggers of seasonal allergies worldwide. Depending on the season, weeds, grasses and trees release pollen to fertilize their own species. The wind travels the tiny and light pollen but unfortunately they end up in our noses, eyes and lungs as well.With their powdery, granular appearance they look quite delicate and innocent. In some people they will however trigger an allergic reaction. We mostly relate to this as hay fever. Most common symptoms are a runny nose, sneezing, itchy eyes but sometimes also symptoms of the lower airways (asthma). In allergy-prone individuals, their immune system reacts to allergenic proteins by generation of IgE antibodies, a process called sensitization. These antibodies will bind to receptors on mast cells and basophils, the effector cells of allergic diseases. If a pollen-sensitized person then gets exposed in pollen season, these effector cells release various mediators such as histamine. These mediators together are at the basis of starting off the allergic symptoms.