The Effect of Allergen Immunotherapy on the Development of New Sensitization in Children

Aim: The protective effect of allergen immunotherapy against a new allergic sensitization is controversial. This study aimed to investigate the effect of allergen immunotherapy on new allergic sensitization in children. Materials and Methods: The study included 50 patients who received immunotherapy for at least 3 years, and whose skin prick tests were repeated at intervals of at least 3 years (31 patients for house dust mite immunotherapy, 19 patients for pollen immunotherapy), and 69 controls with similar characteristics. Results: The number of patients who developed a new sensitization was similar both in the groups of patients who received house dust mite and pollen immunotherapy, and the control group. There was no significant difference between the first and last skin prick tests of the patients who received house dust mite and pollen immunotherapy; however, in the control groups, a significant increase in sensitivity to tree pollens (n = 2, 5.4%; n = 8, 21.6%) and weed pollens (n = 7, 26.9%; n = 14, 53.8%) was detected (P = .031 and P = .039). While allergen sensitivities in the first tests of the pollen immunotherapy group and the control group were similar, weed pollen sensitivity was significantly higher in the last tests of the control group (n = 14, 53.8%; n = 4, 21.1%, P = .027). It was determined that the presence of weed pollen sensitization (OR: 8.1, 95% CI: 1.5-42.4) and having asthma (OR: 3.5, 95% CI:1.3-10.8) increases the risk of new sensitization in all groups. Conclusion: Allergen immunotherapy has been found to protect against new sensitization to tree and weed pollens. However, this effect was insignificant in the multivariate analysis. Weed pollen sensitization and the presence of asthma are related to the development of new sensitization.