Effectiveness of a penicillin allergy delabeling program-real-world data from Croatia.

Penicillin allergy is the most commonly reported drug allergy, often leading to unnecessary avoidance of beta-lactam antibiotics, increased use of alternative broad-spectrum antibiotics, and higher healthcare costs. However, studies indicate that over 90% of penicillin allergy labels are erroneous. This study presents real-world data from a penicillin allergy delabeling program conducted at the Special Hospital for Pulmonary Diseases in Zagreb, Croatia. A total of 132 adult patients with a reported beta-lactam allergy were evaluated with a stepwise diagnostic protocol, including medical history review, skin tests, specific IgE, and drug provocation tests. Five patients were delabeled directly, while 127 underwent diagnostic testing. Among 121 participants who completed the protocol, penicillin allergy was confirmed in 13 (10.74%) patients, and the label was retained in an additional 3 patients because of high-risk history, resulting in an overall confirmed allergy rate of 13.2%. The negative predictive values for STs were 99.07% and 94.39% for immediate and delayed reactions, respectively, while the NPV of sIgE for immediate reactions was 100%. No severe reactions occurred during the diagnostic process. Hundred and five out of one hundred and thirty two (79.5%) patients were safely delabeled. These findings confirm the safety and effectiveness of PAD programs in outpatient settings and highlight the potential for improving antibiotic stewardship by reducing unnecessary beta-lactam avoidance.