A systematic review and economic evaluation of subcutaneous and sublingual allergen immunotherapy in adults and children with seasonal allergic rhinitis

Allergic rhinitis (AR) is an immunoglobulin E (IgE)-mediated inflammation of the nasal mucosa following allergen exposure. Symptoms include rhinorrhoea, nasal obstruction, nasal itching and sneezing. AR is often comorbid with allergic conjunctivitis and is a risk factor for asthma.(1) Depending on the nature of the triggering allergen, AR has traditionally been categorised as either seasonal allergic rhinitis (SAR, e.g. induced by pollen) or perennial allergic rhinitis (PAR, e. g. induced by animals, dust mites, etc.). More recently, an alternative classification of either intermittent or persistent AR has been proposed [Allergic Rhinitis and its Impact on Asthma (ARIA) 2008 update].(1) The disease can further be categorised as either 'mild' or 'moderate/severe', depending on the severity of symptoms and impact on quality of life (QoL).(1) 'Hay fever' is the common name classically given to SAR or rhinoconjunctivitis. Diagnosis is based on symptom history and examination, and could include investigations such as peak nasal inspiratory flow or nasal endoscopy. Skin prick tests should be carried out routinely in order to determine whether rhinitis is allergic or non-allergic.(2)