CEFAZOLIN HYPERSENSITIVITY: A CASE OF OPTIMIZED CLARIFICATION

Introduction Antibiotics are the most common cause of perioperative anaphylaxis in the United States. Patients who have perioperative anaphylaxis due to cefazolin are often labeled as penicillin allergic, however many are selectively allergic to cefazolin, leading to unnecessary avoidance of penicillin. Case Description A 69-year-old male who developed perioperative anaphylaxis in the setting of robotic nephroureterectomy. During the procedure he had received cefazolin, midazolam, rocuronium, propofol, fentanyl, and lidocaine. Perioperatively he was noted to have urticarial lesions over his entire body as well as significant angioedema of the face. Tryptase drawn at that time was 15 ng/mL (normal Discussion This case builds upon the limited evidence that selective IgE- mediated hypersensitivity to cefazolin is responsible for immediate severe allergic reactions in the perioperative period and that patients in this scenario can often tolerate other beta-lactams antibiotics. This pattern is likely explained by the selectivity of the R1 side chain of cefazolin. A complete evaluation including skin testing to a panel including penicillin is essential to ensure accurate diagnosis and to avoid unnecessary avoidance of penicillins.