Optimal duration of allergen immunotherapy in children with dust mite respiratory allergy

BackgroundSubcutaneous immunotherapy (SCIT) discontinuation data in children remain scarce. ObjectiveWe sought for differences in the clinical efficacy of 3 vs. 5yr of SCIT in children with dust mite respiratory allergy. MethodsWe performed a 5-yr, phase IV prospective study. After the first year, the patients were randomized to 3 (IT3) or 5yr of treatment (IT5). Efficacy was assessed at 3rd and 5th year by symptom and medication scores and visual analog scales (VAS). Skin tests with common allergens and in vitro assessments were also performed. ResultsEighty-one children (mean age: 9yr) were randomly assigned to 3 (IT3: 41) or 5yr (IT5: 40) of immunotherapy. After 3years, rhinitis global scores decreased in IT3 (44%; p=0.002) and in IT5 (50%; p=0.001). Asthma global, symptom and medication scores decreased by 100% in IT3 (p=0.001) and IT5 (p=0.001). VAS scores also diminished significantly (IT3: 70%, p=0.001; IT5: 62.5%; p=0.001). At 5th year, global rhinitis scores were reduced an additional 30% in IT5 children. Comparisons between both groups did not show differences in rhinitis (p=0.055), asthma global scores (p=0.948) or VAS scores at 5th year. Twenty percent of IT5 (p=0.002) and 7% of IT3 children (p=0.705) developed new sensitizations. At 5th year, sIgG4 determinations decreased in IT3 without significant variations in IT5. ConclusionsThree years of SCIT induced significant improvement in children with dust mite respiratory allergy, but a 5-yr course added clinical improvement in rhinitis.