What Is Hay Fever (Allergic Rhinitis)?

Hay fever or allergic rhinitis is a common allergic reaction that causes sneezing, coughing and itchy eyes. It occurs when the body reacts to harmless substances (called allergens) such as pollen or dust. These allergens cause the immune system to release a chemical called histamine, leading to all the familiar symptoms.

Generally considered a seasonal allergy, hay fever may also be classed as perennial (lasting year-round) but is distinct from those that are truly perennial. True perennial allergies are triggered by constant exposures to outdoor allergens like dust mites, mould spores or pet dander(tiny flakes of skin), present throughout the year. In contrast, seasonal allergies such as hay fever are linked to fluctuating pollen counts that vary with the seasons.

Food allergies are another type of immune response involving proteins in specific foods such as nuts, shellfish or milk. There is a phenomenon called oral allergy syndrome (OAS), where people with hay fever may be more susceptible to food allergies due to similarities between pollen and food proteins.

True food allergies are a form of severe allergic reactions which, due to their life threatening nature, require immediate treatment with adrenaline auto injectors (Epi-pen).