Suspected penicillin allergy: risk assessment using an algorithm as an antibiotic stewardship project

Background: Beta-lactam antibiotics (BLA) are the treatment of choice for a large number of bacterial infections. Putative BLA allergies are often reported by patients, but rarely confirmed. Many patients do not receive BLA due to suspected allergy. There is no systematic approach to risk stratification in the case of a history of suspected BLA allergy. Methods: Using the available stratification programs and taking current guidelines into account, an algorithm for risk stratification, including recommendations on the use of antibiotics in cases of compellingly indicated BLA despite suspected BLA allergy, was formulated by the authors for their maximum care university hospital. Results: The hospital is in great need of recommendations on how to deal with BLA allergies. Patient-reported information in the history forms the basis for classifying the reactions into four risk categories: (1) BLA allergy excluded, (2) benign delayed reaction, (3) immediate reaction, and (4) severe cutaneous and extracutaneous drug reaction. Recommendations strictly depend on this classification and range from use of full-dose BLA or use of BLA under certain conditions (e.g., two-stage dose escalation, non-cross-reactive BLA only) to prohibiting all BLA and the use of alternative non-BLA. In case of suspected immediate or delayed allergic reactions, there is an additional recommendation regarding subsequent allergy testing during a symptom-free interval. Conclusion: Triage of patients with suspected BLA is urgently required. While allergy testing, including provocation testing, represents the most reliable solution, this is not feasible in all patients due to the high prevalence of BLA allergies. The risk stratification algorithm developed for the authors’ hospital represents a tool suitable to making a contribution to rational antibiotic therapy.