D1.258 - Comparison of the Negative Predictive Values of One-Day and Five-Day Drug Provocation Tests in Late-Mild and Cutaneous Beta-Lactam Allergies in Children

There is no standardized recommendation about the duration of the drug provocation tests (DPTs) while confirm or rule out beta-lactam hypersensitivity reactions (BL-HSR), and different opinions exist on this matter. This study aimed to evaluate the negative predictive values (NPV) of one-day and five-day provocation tests performed on pediatric patients who presented to our clinic with suspected late-mild and cutaneous beta-lactam allergy.

A retrospective analysis was conducted on pediatric patients (<18 years) with suspected late-mild and cutaneous BL-HSR who were admitted to our pediatric allergy clinic between 2016 and 2023. Patient demographics, reaction characteristics, culprit drugs, provocation test, and out comes were recorded. DPTs were classified as one-day or five-day based on their duration. The subsequent use of the culprit drug and outcomes were also investigated .

The study included 173 patients with a median age of 7 years (IQR: 4-10.5), of whom 50.9% were male. Atopic comorbidities were present in 29.5% of patients (allergic rhinitis: 13.9%, asthma: 15%, atopic dermatitis: 2.3%). The median age at reaction onset was 4 years (IQR: 2-7 years), and patients admitted to the clinic a median of 11 months (IQR: 3-24 months) after the reaction. DPTs were performed at a median of 11 months (IQR: 3-36 months) after the reaction.

During the provocation tests, reactions occurred in 8 patients (4.6%) in the hospital and in 2 patients (1.2%) after discharge. One-day provocation tests wereperformed in 53.1% of patients, while 46.8% underwent five-day tests. Despite negative DPT results, 19% of patients did not reuse the drug, 19.6% were unreachable, and 55.4% reused the culprit drug. Among those who reused the drug, 11 patients (6 from theone-day group and 5 from the five-day group; p = 0.768) experienced a recurrence of symptoms. The NPV was 86.4% for the one-day DPT and 90.4% for the five-day DPT. These 11 patients were invited for re-provocation; so far, 3 have undergone repeat testing, with 2 yielding negative and 1 yielding positive results. The remaining re-provocation tests are stil ongoing.

The negative predictive values of one-day and five-day drug provocation tests performed to confirm late-mild and cutaneous BL-HSR were found to be similar.