Frequency of new sensitization in patients experiencing symptom recurrence during allergen immunotherapy

Introduction
Allergen immunotherapy should be personalized according to the allergen sensitization pattern and the clinical impact of allergens. Sensitization, or the existence of antibodies for specific allergens, is a necessary step for developing an allergic reaction to an allergen. The sensitisation pattern may vary over time. This research aimed to assess the frequency of new sensitization in cases with respiratory allergies and experiencing recurrence of allergic symptoms during subcutaneous allergen immunotherapy.


Patients and methods
This study was performed on known patients of allergic airway diseases (allergic rhinitis, bronchial asthma) and subjected to subcutaneous allergen immunotherapy for a minimum of 2-year intervals.


Results
The recurrence of allergic symptoms during allergen immunotherapy was reported in 18.6% of the patients studied. New sensitization was detected in 56.2% of them (34.3% had new pollen sensitization). Most new pollen and hay sensitizations were noticed in patients who experienced symptom recurrence in the third year of therapy.


Conclusion
New sensitization often occurs in patients who experience symptom recurrence during allergen immunotherapy. Therefore, repeating skin prick tests to identify new sensitization patterns is recommended for these patients.