OBJECTIVES: To assess the long-term burden of asthma in children with allergic rhinitis/conjunctivitis. METHODS: We reviewed the literature on incidence of asthma in patients with allergy. Furthermore we estimated long-term outcomes associated with allergic rhinitis/conjunctivitis in children using a Markov health state model. The model was populated using data from a long-term prospective follow-up, where asthma status was recorded up to 10 years in patients receiving only symptomatic treatment for allergy and asthma symptoms. The model was used to explore the impact of key drivers of long-term patient outcomes. Burden to patient was measured as the difference between net present value of QALYs and life-years. RESULTS: Allergic rhinitis/conjunctivitis in childhood is associated with a risk of developing asthma. The asthma risk is highest at younger age and decreases as the child reaches adolescence and adult age. Furthermore, allergic rhinitis is a risk factor for childhood allergic asthma to persist into middle age. The model analysis showed that in per one hundred 10-year old patients with hay fever, but no previous asthma: 57 will develop asthma over a 10 years horizon; In total 55 QALYs are lost over a 10 years horizon of which 67% is attributable to allergic asthma; and Additional 23 respectively 43 QALYs are lost when analyzing on a 15 respectively 20 years horizon even when assuming no additional cases occur after year 10. CONCLUSIONS: Childhood allergic rhinitis is a risk factor for developing allergic asthma in childhood/ preadolescence. Allergic asthma in turn has a pro-found effect on the long-term burden of allergic rhinitis/conjunctivitis. Literature suggests that childhood asthma may impact on quality of life also when the patient reaches middle age. Taken together this suggests a large potential for specific immunotherapy with disease-modifying properties to reduce the burden of allergy and allergic asthma.