Polysensitization as a challenge for the allergist: the suggestions provided by the Polysensitization Impact on Allergen Immunotherapy studies

INTRODUCTION: Polysensitization, that is, sensitization to more than one allergen family, is a common feature of patients with allergic rhinitis (AR) and significantly impairs their quality of life (QoL). Allergen-specific immunotherapy is the only causal treatment for AR. However, the polysensitization phenomenon may represent a crucial obstacle as far as it concerns the choice of the allergen extract to be used for immunotherapy. AREAS COVERED: A series of real-life based multi-center studies, named POLISMAIL (Polysensitization Impact on Allergen Immunotherapy), have been designed with the aim of evaluating the behavior of allergists in managing polysensitized AR patients. The effect of immunotherapy treatment in these patients was also evaluated. A single allergen extract was used in two-thirds of patients, whereas a mix of two allergens was chosen in the remaining. The severity grade of AR and the QoL were significantly improved by immunotherapy. Both outcomes confirmed that immunotherapy with one or two allergen extracts achieves a significant improvement in polysensitized patients. EXPERT OPINION: In conclusion, POLISMAIL studies demonstrate that polysensitization should not represent a counter-indication for prescribing immunotherapy. The choice of limiting sublingual immunotherapy to one to two allergen extracts, preferably separated and at high dosages, is sufficient and effective in improving symptoms and QoL.