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.