Allergen Specific Immunotherapy in Asthma

The use of allergen-Specific Immunotherapy (SIT) to treat asthma remains one of the most debated aspects in the field since several decades. The available guidelines provide no clear or unequivocal indication, stating only that SIT is specific for the allergen causing the allergic disease (rhinitis and/or asthma) and not for the disease itself [1]. Nonetheless, in the majority of the clinical trials, the efficacy of SIT has been evaluated separately for the two disorders, rhinitis and asthma, [27] and only few trials were specifically designed to evaluate the impact of SIT on asthma. This is due to the fact that in real life, isolated allergic asthma without rhinitis is infrequent and more than 30% of patients with allergic rhinitis also suffer from allergic asthma [8]. Another problem is that none of the trials evaluating asthma symptoms has been adequately designed and reported. A sample size calculation and a power analysis based on asthma symptoms alone were not ever used as primary outcome in any trial [9]. Moreover, a formal consensus on which measurement parameter for evaluating asthma should be chosen is still missing. In this regard, asthma symptoms, rescue medications intake, combined scores, asthma-free days, asthma exacerbations are all equally reasonable choices [10], however, objective functional pulmonary measurements such as Forced Expiratory Volume in one second (FEV1) were carried out only sporadically [11].