title: Cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins.
abstract: OBJECTIVE
  13-Lactams are the most commonly used antibiotics but they can cause hypersensitivity reactions. We sought to estimate cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins.
  
  
  METHODS
  We studied 97 patients with a clinical history of nonimmediate reactions to a penicillin and a positive patch test result to at least 1 of the penicillins tested. All patients also underwent patch testing with several cephalosporins. Patients with a negative patch test to a cephalosporin underwent test dosing in order to assess tolerability.
  
  
  RESULTS
  We recorded 129 reactions. The most commonly involved drugs were aminopenicillins, and the most widely reported symptoms were delayed urticaria and maculopapular exanthema. Seventeen patients had positive patch test results for cephalosporins, mostly for cephalexin (n=10), cefaclor (n=9), and cefuroxime axetil (n=5). All the patients-except 4 who experienced an exanthema after the challenge test with cephalexin-tolerated a therapeutic dose of the cephalosporin tested without any adverse effects.
  
  
  CONCLUSIONS
  Our data show that cross-reactivity between penicillins and cephalosporins may be as high as 10.9% for first-generation cephalosporins and 1.1% for third-generation cephalosporins, possibly due to the involvement of similar side chains. Patch tests are a useful diagnostic tool to assess cross-reactivity, but a graded challenge is mandatory because a negative patch test does not always mean tolerability.
authors.forename: A
authors.initials: A
authors.lastname: Buonomo
authors.forename: E
authors.initials: E
authors.lastname: Nucera
authors.forename: V
authors.initials: V
authors.lastname: Pecora
authors.forename: A
authors.initials: A
authors.lastname: Rizzi
authors.forename: A
authors.initials: A
authors.lastname: Aruanno
authors.forename: L
authors.initials: L
authors.lastname: Pascolini
authors.forename: A G
authors.initials: AG
authors.lastname: Ricci
authors.forename: A
authors.initials: A
authors.lastname: Colagiovanni
authors.forename: D
authors.initials: D
authors.lastname: Schiavino
mesh_terms: D000328:Adult; D000368:Aged; D002511:Cephalosporins / Q000009:adverse effects / Q000276:immunology*; D003429:Cross Reactions; D004342:Drug Hypersensitivity / Q000276:immunology*; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000276:immunology*
chemical_list: D002511:Cephalosporins; D010406:Penicillins