What are the causes behind the hay fever? Hay fever, also referred to as seasonal allergic rhinitis or seasonal allergies, is an allergic response caused by pollen. The allergy occurs when a person’s immune system reacts to pollen(allergens) and releases chemicals into the bloodstream to defend against those allergens. Seasonal allergic rhinitis is common during the summer and spring months. Know more: https://www.hayfeverinjection.com/