Predictive factors of amoxicillin immediate hypersensitivity and validation of PEN-FAST clinical decision rule.

Abstract

Challenge of delabeling amoxicillin allergy is a significant issue for patients and clinicians, especially when anaphylaxis is reported. A recent study has proposed a clinical decision rule, PEN-FAST, to identify low-risk penicillin allergies. We sought TO: validate the PEN-FAST clinical decision rule in a population with high risk of suspected immediate amoxicillin allergy and to identify clinical predictive factors of amoxicillin immediate hypersensitivity. We RETROSPECTIVELY: analyzed medical records of patients with a suspected immediate amoxicillin allergy who carried out an allergological evaluation by a specialist in the Allergy Unit of Strasbourg University Hospital from 2015 to 2020. A total of 142 ADULT: patients (88 females [62.0%]; median age, 52 [interquartile range, 40.3-62.0] years) were analyzed. Most of them reported anaphylaxis (68,8%). Internal validation of PEN-FAST score showed a good discrimination with area under the curve of 0.86 (95% CI, 0.79-0.92). A cutoff of less than 3 points for PEN-FAST was used to classify 29 from 142 patients at low risk of allergy, of whom only 2 (6,9%) had positive results of allergy testing. The negative predictive value for successful delabeling was 0.93 (95% CI, 0.77-0.99). Predictive clinical features for immediate amoxicillin hypersensitivity were time since reaction (p<0.001), time elapsed between drug intake and first symptom (p<0.001), severity grade reaction (p<0.001) and treatment or hospitalization required (p<0.001). PEN-FAST has been validated to identify low-risk penicillin allergies in our European cohort of patients mainly reporting anaphylaxis. This is the first reported external validation of a penicillin allergy clinical decision rule internationally. Concept and design: Piotin, de Blay, Metz-Favre. Acquisition, analysis, or interpretation of data: All authors.Drafting of the manuscript: Piotin, de Blay, Metz-Favre. Critical revision of the manuscript for important intellectual content: All authors. All authors except Frédéric de Blay have no conflict of interest. Frédéric de Blay perceived financial support: Clinical Grants (Aimmune, Stallergènes-Greer, ALK, Novartis, AstraZeneca, DBV, Sanofi, GSK), board membership (Aimmune, Stallergènes Greer, ALK, Novartis, AstraZeneca, DBV, Sanofi). none.