BACKGROUND: Beta-lactam antibiotics (BLAs) commonly cause hypersensitivity reactions in children. These reactions are categorized into immediate reactions, which include urticaria, angioedema, bronchospasm, and anaphylaxis, and non-immediate reactions, such as maculopapular rashes and delayed-onset urticaria/angioedema. Rashes in children, often caused by infections, may be misdiagnosed as BLA allergy. However, over 90% tolerate the medication following an allergic evaluation.
METHODS: We aimed to evaluate patients with negative single-day drug provocation test (sdDPT) results for subsequent reactions and to determine the negative predictive value (NPV) of sdDPT for immediate (less than 1 h) and non-immediate (more than 1 h) suspected BLA allergy. In addition, non-immediate reactions were assessed by classifying them as occurring within 1-6 h or after 6 h. Patients who underwent sdDPT for suspected BLA allergy and tested negative between 2019 and 2023 were included in the study. They were questioned via telephone interviews about their reuse of the tested drug.
RESULTS: 404 patients who underwent sdDPT for suspected BLA allergy were evaluated. The NPV of BLA sdDPT was determined to be 97.3%. When patients were categorized based on the time interval between the last dose and the reaction, the NPV was 97% for those experiencing a reaction within the first hour of drug use and 96.7% for reactions occurring after more than 1 h. Non-immediate reactions were further evaluated, revealing an NPV of 98.7% for reactions occurring between 1 and 6 h, and 92.5% for reactions occurring after 6 h.
CONCLUSIONS: Our findings demonstrate that sdDPT has a high NPV for both immediate and non-immediate reactions. However, the NPV of sdDPT was lower for reactions occurring more than 6 h after the last dose.

There is currently no standardized duration of drug provocation test (DPT) for confirming/delabeling beta-lactam hypersensitivity reaction (BL-HSR).
This meta-analysis and systematic review aimed to investigate the added diagnostic value of extended-day over single-day DPT for confirming/delabeling BL-HSR in adults and children.
The MEDLINE, EMBASE, Web of Science, and CINAHL online databases were searched from inception to March 15, 2023, for studies that performed extended-day DPT to confirm/delabel BL-HSR. Risk difference and risk ratio were used to compare the proportions of patients with confirmed BL-HSR by single-day or extended-day DPT.
A total of 10,371 DPTs from 42 studies were included. Extended-day DPTs ranged from 2 to 7 days, or as long as index reactions were reported (maximum 10 days). The overall prevalence of confirmed BL-HSR was 6.96% (3.31% during the first-day DPT, and 3.65% during extended-day DPT). Approximately half of the positive reactions during extended-day DPT occurred during the second/third day. The increased detected pool prevalence of confirmed BL-HSR yielded by extended-day DPT was 0.03 (95% CI, 0.02%-0.04%; I2 = 57.69%; P < .001), and the risk ratio of positive reactions between extended-day and single-day DPT was 1.94 (95% CI, 1.62-2.33; I2 = 36.26%; P < .001). The risk difference increased per 1% increase in prevalence of BL-HSR by 0.6% (95% CI, 0.4%-0.7%; P < .001). Twenty-three severe reactions occurred during DPT, and only 2 severe reactions (0.02%) occurred during extended-day DPT. An additional 28 extended-day DPTs were needed to identify 1 mild reaction.
The increased prevalence of confirmed BL-HSR observed during extended-day DPT could be attributed to the first-day DPT. As a result, our findings do not conclusively support the use of extended-day DPT over single-day DPT. Further studies, incorporating a washout period, are required to comprehensively compare these 2 approaches.