title: Skin testing only with penicillin G in children with a history of penicillin allergy.
abstract: BACKGROUND
  The absence of commercially available penicilloyl-polylysine (PPL) for most of the last decade severely hampered the practice of penicillin allergy evaluation because skin testing without PPL is reported to have a poor negative predictive value (NPV).
  
  
  OBJECTIVE
  To determine the safety and NPV of skin testing without PPL using only penicillin G followed by a 3-dose graded challenge to the incriminated penicillin in children with a history of penicillin allergy.
  
  
  METHODS
  Patients evaluated for a history of penicillin allergy at the CHU Sainte-Justine Allergy Clinic between December 2006 and December 2009 were skin tested only with penicillin G and underwent a 3-dose graded challenge to the culprit penicillin if the skin test result was negative.
  
  
  RESULTS
  Among 563 patients skin tested to penicillin G, 185 (33%) had a positive skin test result. These patients had a shorter interval between the initial reaction and skin testing compared with patients with a negative skin test result (P = .03). A total of 375 of 378 patients (99%) with a negative skin test result were challenged and 18 (4.8%) reacted, translating into a NPV of 95.2% (95% confidence interval [CI], 92.5%-97.1%). Three of 17 patients with a history of anaphylaxis and a negative skin test result reacted to challenge (NPV, 82.4%; 95% CI, 59.0-93.8%). All challenge reactions were mild and resolved promptly with treatment.
  
  
  CONCLUSIONS
  Among children with a history of penicillin allergy, skin testing only with penicillin G followed by a 3-dose graded challenge to the incriminated penicillin is safe and yields a good NPV. This approach could be useful when PPL is unavailable.
authors.affiliation: Division of Allergy, Department of Pediatrics, CHU Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Picard
authors.affiliation: Division of Allergy, Department of Pediatrics, CHU Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: Louis
authors.initials: L
authors.lastname: Paradis
authors.affiliation: Division of Allergy, Department of Pediatrics, CHU Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bégin
authors.affiliation: Division of Allergy, Department of Medicine, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Paradis
authors.affiliation: Division of Allergy, Department of Pediatrics, CHU Sainte-Justine, Montreal, Quebec, Canada. Electronic address: a.des.roches@umontreal.ca.
authors.forename: Anne
authors.initials: A
authors.lastname: Des Roches
mesh_terms: D000293:Adolescent; D044482:Benzeneacetamides; D002648:Child; D002675:Child, Preschool; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010397:Penicillanic Acid / Q000031:analogs & derivatives; D010400:Penicillin G / Q000008:administration & dosage / Q000276:immunology*; D011107:Polylysine / Q000031:analogs & derivatives; D011237:Predictive Value of Tests; D012882:Skin Tests / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D044482:Benzeneacetamides; D011107:Polylysine; C003058:penicilloyl polylysine; D010397:Penicillanic Acid; D010400:Penicillin G