SELECTING SKIN TESTING REAGENTS TO PREDICT AMOXICILLIN AND CEPHALOSPORIN ALLERGY

Objectives: This study assessed the accuracy of a panel of skin testin g reagents to detect immunoglobulin E sensitivity to amoxicillin and o ral cephalosporins. Methods: One hundred and eighty-seven children and adolescents experiencing adverse reactions to amoxicillin (or amoxici llin/clavulanate), and/or an oral cephalosporin, that were considered sufficient to preclude further use were studied, Skin testing with pen icillin G, commercial benzylpenicilloyl phosphate, penicillin minor de terminant mixture (MDM), ampicillin, cefazolin, cefuroxime, and ceftri axone was performed according to the suspected drug allergy, followed by an oral challenge, repeat skin testing, and prospective follow-up i f no reactions mere observed. Results: Fifty-four (33.5%) of 161 patie nts with suspected amoxicillin reactions and 13 (50%) of 26 suspected cephalosporin reactions had positive skin tests or oral challenges, Po sitive reactions to only the MDM reagent occurred in 9 amoxicillin-or cephalosporin-allergic patients, to only the ampicillin reagent in 4 a moxillin-allergic patients, and to only a cephalosporin reagent in 3 c ephalosporin-allergic patients. No reactions to oral challenge were se vere after negative skin testing. During prospective follow-up, one (0 .9%) of 107 patients suspected of amoxicillin allergy who completed ou r skin testing-oral challenge repeat skin test protocol without a reac tion and two (1.8%) patients with borderline reactions subsequently de veloped urticaria 8-16 months later while taking a course of amoxicill in, Reactions were mild. No test negative patients suspected of cephal osporin allergy developed a reaction with a subsequent course of a cep halosporin. Amoxicillin reactors with positive skin tests or oral chal lenges (N = 54) received 83 treatment courses of cephalosporins uneven tfully in prospective follow-up, Conclusions: Elective amoxicillin and cephalosporin skin testing and oral challenge protocols are helpful i n identifying patients at very low risk for developing subsequent hype rsensitivity reactions. Pediatr Asthma Allergy Immunol (1997;11[2]:79- 93.)