Usefulness of skin tests in penicillin-allergic patients after cephalosporins challenge

摘要

BackgroundSubjects with a history of documented penicillin allergybut with negative skin test results for cephalosporins, cantolerate subsequent challenge doses of cephalosporin withoutan allergic reaction. [1]. In immediate reactions tobetalactams (BL), in some instances, specificity was mainlydirected to the BL inducing the reaction, but in othercases specificity was mainly directed to another structure,probably related with previous BL exposure [2].MethodsBetween November 2011 and October 2013, we prospectivelyrecruited a total population of 100 (71 women,29 men) patients from the outpatients of the ClinicalImmunology Unit (Florence, Italy). Patients had a historyof immediate reactions to at least one penicillin (Tab. 1)and positive results on skin tests for one or more penicillinreagents (penicilloyl-polylysine, minor determinant mixture,and benzylpenicillin), one or more semi-syntheticpenicillins (amoxicillin, ampicillin), or both [3]. We alsoevaluated sensitization to cephalosporins by using skintests [4] with second-generation (cefuroxime), and thirdgeneration(ceftazidime, ceftriaxone, and cefotaxime)cephalosporins. In cases of negative results for all of thesecefalosporins, cefuroxime and ceftriaxone were administeredto consenting patients [1].Results74 of the 100 patients underwent challenges with oralcefuroxime axetil and intramuscular ceftriaxone: all toleratedthe challenge. After about a month we repeatedthe skin tests with PPL, MDM, and the two cephalosporinsadministered (cefuroxime and ceftriaxone).8 patients (10.8%) presented new sensitizations: 2 forMDM, 2 for PPL and MDM, 1 for cefuroxime, 1 for ceftriaxone,1 for PPL and ceftriaxone, 1 for PPL, MDM,cefuroxime and ceftriaxone. 26 patients refused the doublechallenge and only underwent a tolerance to cefuroximeaxetil test. In one of these the challenge waspositive. The skin tests after a month with PPL, MDM,and the cephalosporin administered (cefuroxime) presentednew sensitizations in only one patient (4.0%),for PPL.ConclusionOne month after the challenge, the percentage of sensitizationseems to be higher in patients who underwent tolerancetests with two cephalosporins. It would be useful tohave more data available to confirm the above mentionedassumptions, but above all it would be useful to know ifwe can recommend the cephalosporins tolerated withnegative skin tests after a month, even if associated withpositive PPL and/or MDM and/or other cephalosporinadministered with the tolerance test.