Pollinosis is also known as pollen allergy, allergic rhinitis or hay fever. It is an allergic reaction caused by the tiny particles present in the air called allergens. They get to enter your body through the nose or mouth when you breathe and triggers the immune system. It mistakenly identifies that substance as harmful and starts producing antibodies to defend your body. Antibodies then signal the blood vessels to widen and produce inflammatory chemicals such as histamine. It is this response that causes Pollinosis symptoms.