Patient exposure to allergens healthcare settings, such as latex or certain medications, can lead to adverse outcomes. Based on data from an incident reporting system, researchers in this study developed a system for classifying allergy-related safety events. Classification categories include: (1) incomplete or inaccurate EHR documentation, (2) human factors, such as overridden allergy alerts, (3) alert limitation or malfunction, (4) data exchange and interoperability failures, and (5) issues with EHR system default options. This classification system can be used to support improvements at the individual, team, and systems levels.