Defining allergic rhinitis

Allergic rhinitis (AR) is a symptomatic disorder of the nose induced after allergen exposure by IgE-mediated (type I hypersensitivity) inflammation. The characteristic symptoms are sneezing, rhinorrhoea (runny nose and/or post-nasal drip), nasal itching and obstruction, but the severity of symptoms can vary considerably. 

There has been a steady increase in prevalence in the UK and Western Europe over the past 50 years – in the UK the prevalence of AR in adults is 26 per cent. Depending on the allergen(s) responsible, it can be intermittent (e.g. hayfever) or persistent (e.g. caused by allergy to house dust mites, animal dander or occupational allergens such as latex particles). AR can be associated with allergic conjunctivitis, asthma and eczema, as well as the development of nasal polyps that further obstruct nasal passages.

AR is more common in individuals with a personal or family history of atopic disease and is one component of the ‘atopic march’ – the phenomenon of disordered immune responses that starts with skin barrier defects in infancy leading to the progressive development of atopic eczema, food allergy, asthma and allergic rhinitis. Atopy is typically associated with heightened immune responses to common allergens, especially inhaled and food allergens.