Allergic rhinitis (AR) refers to a disease process resulting in nasal mucosal inflammation causing symptoms of blockage, running, sneezing and itching. It is caused by the exposure of genetically predisposed individuals to inhaled proteins termed aeroallergens to which they have previously become sensitised. This has resulted in the production of specific immunoglobulins of type E (IgE) that have bound to mast cells. When the aeroallergen binds to the IgE molecules, the mast cell degranulates, releasing histamine and other drivers of inflammation. The disease is common, affecting 25% of the Western population, though is much less prevalent in the developing world. There are strong links with asthma, and AR is now seen as being part of a systemic disease process termed the unified allergic airway. The diagnosis and treatment of AR has been of limited efficacy in the past, leading to a significant reduction in the quality of life for some patients. Although antihistamines and topical corticosteroids remain the mainstay of treatment, immunotherapy is being used more widely and there are a number of promising monoclonal antibodies that may significantly improve treatment success in the future.