Allergic rhinitis is an inflammation of the nasal mucosa which is triggered by an allergic reaction.
The inflammation is caused by an excessive degranulation of mast cells. Increased IgE levels to certain allergens are thought to be responsible for this phenomenon. When exposed to these allergens, the IgE covered mast cells degranulate releasing inflammatory mediators and cytokines which results in a local inflammatory reaction. Epidemiology Over the last couple of decades, there appears to have been an increase in the prevalence of allergic rhinitis. This increase is partially attributable to the limited ventilation in most modern housing.