Supplementary Material for: Perioperative Hypersensitivity Reactions: An Analysis of Affected Patients, Responsible Agents, and Conducted Diagnostics at a Tertiary Allergology University Center in Switzerland

Introduction: Perioperative hypersensitivity reactions (POH) are rare occurrences, but they can lead to life-threatening complications. The culprits for POH vary between countries. In about 25% of the cases, the causative agent of POH remains unknown. Objective: Data on POH and its causes in Switzerland are sparse. The aim of this study was to address this gap and provide insights into POH in Switzerland. Methods: In this retrospective monocentric study, we analyzed data from 106 patients referred for POH evaluation to a tertiary Allergology University Center in Switzerland. We analyzed data about clinical characteristics, culprit drugs, and performed diagnostic tests (specific IgEs, basophil activation tests, skin tests, provocation tests). Results: The majority of POH patients were female (56.6%, n=60). Allergic comorbidities were frequently present (68.9%, n=73), a previous episode of POH was reported in 16.0% (n=17). A trigger was diagnostically confirmed or strongly suspected in 76.4% (n=81) of the cases. The most common confirmed or suspected triggers were neuromuscular blocking agents (NMBA) and antibiotics (predominantly cephalosporins), each accounting for 26.5% (n=27) of the reactions. This was followed by antiseptics (9.8%, n=10) and opioids (9.8%, n=10). Latex accounted for less than three percent of the reactions. For the confirmed triggers, identification primarily relied on positive skin test results (73.0%, n=46), although different tests sometimes yielded varying results. Conclusions: In Switzerland, antibiotics (mostly cephalosporins), and NMBA are among the most common triggers of POH. By combining skin tests and in vitro diagnostics, culprit drugs of POH could be identified in more than 75.0% of the cases.