Otherwise known as allergic rhinitis or pollinosis, hayfever is an allergic reaction triggered by allergens such as dust, pollen, mites, grasses, moulds, animal fur/hair and/or air pollution. The condition tends to occur seasonally with outdoor allergens and at any time to those found indoors but can also happen at any time of year too.
Hayfever occurs when allergens become trapped in the fine hairs and mucous membranes of the nasal passages, mouth, throat and lungs. The immune system reacts by stimulating the release of the antibody Immunoglobin E (IgE), which is designed to fight and eliminate the allergens. Histamine is then released from the IgE to flush the allergens out of the airways, which produces a list of symptoms described below.