Diagnosis Of Cephalosporin Allergy Through Graded Oral Challenge: 593

Abstract

S U N D A Y Zahia Attari, Sofianne Gabrielli, MSc, Bahar Torabi, MD, MSc, Christine Lejtenyi, MD, Andrew O’Keefe, MD, Adelle R. Atkinson, MD, Vy Hong-Diep Kim, MD FRCPC, Thomas Eiwegger, MD, Yarden Yanishevsky, MD, MRCPI, FACAAI, FAAAAI, Christine T. McCusker, MD, and Moshe Ben-Shoshan, MD, MSc; Faculty of Medicine, McGill University, Montreal, QC, Canada, McGill University Health Centre, Montreal, QC, Canada, Clinical Instructor, Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada, Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, McGill University Health Centre, Montreal, QC, Canada, Department of Pediatrics, Faculty of Medicine, Memorial University, St. John’s, NF, Canada, Division of Allergy and Clinical Immunology, Department of Paediatrics, Hospital for Sick Children, Toronto, ON, Canada, Division of Immunology and Allergy, Department of Paediatrics, Hospital for Sick Children, Toronto, ON, Canada, Translational Medicine Program, Research Institute, Hospital for Sick Children, Toronto, ON, Canada, Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, Stollery Children’s Hospital, Edmonton, AB, Canada. RATIONALE: Skin testing or specific IgE immunoassays have limited clinical utility for the diagnosis of cephalosporin allergy. We aimed to assess oral cephalosporin antibiotic allergy in children through the use of a graded oral challenge (GOC). METHODS: All children referred to theMontreal Children’s Hospital for suspected cephalosporin allergy were recruited between March 2013 and March 2018. Data were collected through a standardized questionnaire on demographics, clinical characteristics, andmanagement. AGOC (10% and 90% of the oral dose) was conducted to cephalosporin antibiotics excluding ceftriaxone. Multivariate logistic regression was used to estimate factors associated with a positive GOC. RESULTS: Among 101 patients with a reported allergy to cephalosporins, 80.20% reported a reaction to cefprozil, 5.94% to cefixime, 7.92% to cephalexin and 5.94% to other cephalosporins (cefuroxime, cefazolin, cefdinir). The majority of reactions were cutaneous. Among the 89 patients who underwent GOC, 6 (6.74% [95%CI, 2.25%, 13.15%]) had a positive challenge. One reaction (1.12% [95%CI, 0.00%, 7.43%]) was immediate (within 1 hour of the GOC) and 5 (5.62% [95%CI, 1.12%, 11.92%]) were non-immediate. A positive non-immediate reaction to the GOC was more likely in cases treatedwith cephalexin (aOR 1.30 [95%CI, 1.11, 1.52]) while adjusting for sex, age, history of known asthma and food allergy. None of the reactions required epinephrine treatment. Among the 75 patients with negative GOC eligible for follow-up, 42 (56.00%) responded, of which 6 (14.29%) reported cephalosporin use and 1 (16.67% [95%CI, 0.88%, 63.52%]) reacted with a mild rash. CONCLUSIONS: GOCs can be used to safely diagnose cephalosporin antibiotic allergy.