Allergen immunotherapy (AIT) has been evaluated throughout several studies over the last years. A position paper from the European Academy of Allergy and Clinical Immunology highlighted the total combined symptoms score as the method to record the primary end point in AIT studies for allergic rhinitis, but this score still needs to be formally validated and more work done for other allergic diseases. These aspects still seem to be the main unmet need in the evaluation of AIT clinical outcomes in clinical trials.