Supplementary Material for: Subcutaneous Allergen-Specific Immunotherapy Is Safe in Pediatric Patients with Allergic Rhinitis

<b><i>Introduction:</i></b> Subcutaneous allergen-specific immunotherapy (SCIT) is one of the main cornerstones in the treatment of allergic rhinitis in pediatric patients. It has demonstrated symptoms and quality of life improvement, but it is not exempt from adverse reactions (ADVrs). Nevertheless, there are a few reports that have evaluated their safety. Our objective was to evaluate the ADVr to SCIT in pediatric patients. <b><i>Methods:</i></b> We reviewed 786 clinical records with SCIT from 2005 to 2018, comparing the clinical characteristics of patients with ADVrs with SCIT versus a group of a similar number of patients who completed SCIT (control group, CG). The analysis of ADVrs was according to the World Allergy Organization (WAO) 2010 grading system by frequency analysis, survival curve, and log rank. <b><i>Results:</i></b> Of 786 patients, 106 (13.4%) presented ADVrs, and the patients with ADVr had sensitivity and immunotherapy with at least 2 allergens versus CG <i>p</i> &lt; 0.001, containing a combination of standardized and nonstandardized allergens (<i>p</i> = 0.003). The ADVrs were in the buildup phase (<i>p</i> &lt; 0.001). The survival curve showed that 50% had some reaction at 12 weeks of SCIT. The most frequent ADVr was grade 1 in 73/106 patients (68.8%) and grade 2 in 33/106 (31.1%). The log-rank analysis between the grades of the WAO grading system showed a statistically significant difference (<i>p</i> = 0.02). <b><i>Conclusions:</i></b> The SCIT is safe in pediatric patients. The ADVrs are infrequent, grade 1 being the most reported; however, at &gt;12 weeks, the risk of ADVrs that involve 2 organs systems increases.