title: Safe use of selected cephalosporins in penicillin-allergic patients: a meta-analysis.
abstract: BACKGROUND
  Recent analysis of clinical data and a clearer understanding of the role of chemical structure in the development of cross-reactivity indicate that the increased risk of an allergic reaction to a cephalosporin in penicillin-allergic patients is smaller than previously postulated.
  
  
  METHODS
  Medline and EMBASE databases were searched with the keywords: cephalosporin, penicillin, allergy, and cross-sensitivity for the years 1960 through 2005. Among 219 articles retrieved, 9 served as source material for this evidence-based meta-analysis.
  
  
  RESULTS
  A significant increase in allergic reactions to cephalothin (odds ratio [OR] = 2.5; 95% confidence interval [CI] = 1.1 to 5.5), cephaloridine (OR = 8.7; CI = 5.9 to 12.8), and cephalexin (OR = 5.8; CI = 3.6 to 9.2), and all first generation cephalosporins plus cefamandole (OR = 4.8; CI = 3.7 to 6.2) were observed in penicillin allergic patients; no increase was observed with second generation cephalosporins (OR = 1.1; CI, 0.6 to 2.1) or third generation cephalosporins (OR = 0.5; CI = 0.2 to 1.1). Clinical challenges, skin testing, and monoclonal antibody studies point to the paramount importance of similarities in side chain structure to predict cross-allergy between cephalosporins and penicillins.
  
  
  CONCLUSIONS
  First-generation cephalosporins have cross-allergy with penicillins, but cross-allergy is negligible with second- and third-generation cephalosporins. Particular emphasis should be placed on the role of chemical structure in determining the risk of cross-reactivity between specific agents.
authors.affiliation: Department of Microbiology and Immunology, University of Rochester, Elmwood Pediatric Group, Otolaryngology, University of Rochester Medical Center, Rochester, NY, USA. Michael_pichichero@urmc.rochester.edu
authors.forename: Michael E
authors.initials: ME
authors.lastname: Pichichero
authors.forename: Janet R
authors.initials: JR
authors.lastname: Casey
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use*; D000911:Antibodies, Monoclonal / Q000032:analysis; D002435:Cefamandole / Q000009:adverse effects / Q000737:chemistry; D002506:Cephalexin / Q000009:adverse effects / Q000737:chemistry; D002509:Cephaloridine / Q000009:adverse effects / Q000737:chemistry; D002511:Cephalosporins / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use*; D003429:Cross Reactions / Q000276:immunology; D004342:Drug Hypersensitivity / Q000209:etiology* / Q000276:immunology; D019317:Evidence-Based Medicine; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis; D010406:Penicillins / Q000009:adverse effects*; D012449:Safety
chemical_list: D000900:Anti-Bacterial Agents; D000911:Antibodies, Monoclonal; D002511:Cephalosporins; D010406:Penicillins; D007073:Immunoglobulin E; D002435:Cefamandole; D002509:Cephaloridine; D002506:Cephalexin