Evaluation of immediate allergic reactions to cephalosporins in non-penicillin-allergic patients

Background: Cephalosporins can induce severe or life-threatening IgE-mediated reactions in some individuals. In this study, we wish to describe a group of non-penicillin-allergic patients who were evaluated for immediate allergic reactions to cephalosporins. Methods: The patients were assessed by skin tests with the culprit cephalosporin as well as with other cephalosporins and penicillins. If indicated, oral challenge testing was performed. Results: Six patients were assessed. A total of 42 skin tests and 20 oral challenges were performed. In 4 patients, skin tests included the causative drug; in 2 patients, the diagnosis of a cephalosporin allergy was made by skin test; in 4 patients, the diagnosis of a cephalosporin hypersensitivity was made by oral challenge. In 96.9% of the oral challenges, which were done using medications with no structural side chain similarities to the culprit drug, no adverse reaction occurred. Conclusion: A positive skin test to cephalosporin implies the presence of drug-specific IgE antibodies. Cephalosporins without side chain similarities are suggested to patients with cephalosporin reactions and no β-lactam reactivity.