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 beta-lactam reactivity.