Immunotherapy in allergic rhinitis and lower airway outcomes.

Allergic rhinitis and asthma constitute two clinical expressions of a single-condition, respiratory allergy. Allergen immunotherapy (AIT) is a form of treatment specifically aimed at modifying the response to sensitizing allergens. The inherent potential benefit of AIT is the simultaneous treatment of all clinical expressions of respiratory allergy. Current data support the effectiveness of subcutaneous and sublingual immunotherapy in rhinitis. Studies also provide proof for a beneficial effect in allergic asthma. Even more, substantial evidence points to the preventive effect on the progression from rhinitis to asthma. Despite the current knowledge on the basic mechanisms underlying the immunological effect of AIT is vast, the specific mechanisms for the preventive effect of primary sensitization or new sensitizations are poorly understood. This review aimed to provide a critical overview of the current knowledge on the effectiveness of AIT and its potential role in secondary prevention of respiratory allergy progression.