Preventing progression of allergic rhinitis: the role of specific immunotherapy

Allergic rhinitis and asthma are examples of allergic airways disease. Despite their differing symptomatology, both disorders affect the mucosal lining of the respiratory tract and are linked by common underlying cellular processes, thus, using the 'united airways' approach, they can be considered part of the same allergic disease. The conditions are often comorbid, and there is evidence to suggest that allergic rhinitis in children is a significant risk factor for subsequent development of asthma. Management strategies that target the underlying cause of allergic rhinitis in children have the potential to offer additional symptom control above that of symptomatic medications, and prevent disease progression. Specific immunotherapy (SIT) is the only currently available treatment that is proven to target the disease in this way. SIT affects the underlying cause of allergic rhinitis, producing changes in antibody responses to allergens. It has been shown to be effective in the reduction of allergic rhinitis symptoms in both children and adults, with effects being sustained for several years after treatment completion. Furthermore, a number of trials provide evidence that SIT may prevent the development of new sensitisations and asthma in children and adults with allergic rhinitis. One such open-label, randomised controlled study in children/adolescents (the Preventive Allergy Treatment Study) showed that significantly fewer patients who received 3 years of SIT for grass/birch pollen-induced allergic rhinitis had developed asthma 10 years after treatment initiation versus controls. Some clinical guidelines acknowledge this potential asthma preventive effect in children and the need for additional data from double-blind, placebo-controlled trials to support these findings.