Pollen is a fine, powdery grain released from plants, and it can trigger an allergic
reaction in some people. The amount of pollen in the air will vary depending on the
season and where you live. Pollens, once released, can be spread to other places by
insects, birds and the wind.1
Pollen allergy is one of the main causes of hayfever, also called allergic rhinitis. If
you have a pollen allergy, an exposure to pollen can cause you to develop
symptoms such as runny nose, itchy and watery eyes, and sneezing.1
Symptoms occur because your immune system detects an allergy trigger (such as
pollen) and reacts by producing a chemical called histamine to defend against the
foreign substance. Histamine causes the unpleasant symptoms of hayfever.1
Types of pollens that can trigger hayfever
The three main types of pollens that can trigger an allergy are tree, grass and weed
pollens. Some of the plants that fall under each category include: 2,3
-
Tree pollens
Pine tree, oak tree and olive tree
-
Grass pollens
Bermuda grass, canary grass and Johnson grass
-
Weed pollens
Parthenium, pellitory and ragweed
The 3 main pollen allergies that can trigger hayfever