title: Impact of an extended challenge on the effectiveness of β-lactam hypersensitivity investigation.
abstract: BACKGROUND
  Drug provocation tests (DPTs) are the gold standard in the diagnosis of β-lactam hypersensitivity. However, no consensus exists on the need for extended provocation tests, even though the effectiveness of the short DPT is relatively low and there has been an increase in the relative incidence of nonimmediate hypersensitivity reactions.
  
  
  OBJECTIVE
  To evaluate the effectiveness of a 7-day (extended) DPT compared with a 1-day-only (short) DPT in the management of hypersensitivity reactions to β-lactam antibiotics.
  
  
  METHODS
  Patients referred to the allergy clinic of the Sheba Medical Center for suspected β-lactam hypersensitivity from January 2008 to December 2012 underwent in vivo skin tests and an immediate short DPT with the culprit drug. Unless an immediate reaction was clearly documented, patients were offered a 7-day, extended DPT. Long-term effectiveness, calculated as the subsequent use of the tested antibiotic, and satisfaction levels were assessed with a telephone questionnaire.
  
  
  RESULTS
  Of 49 negative DPT results, 26 (53%) were long and 23 (47%) were short. A total of 78% of the patients who underwent the long DPT reported that they used the drug compared with 61% of those who underwent only the short DPT (P = .049). Most patients were very satisfied with the drug allergy evaluation process.
  
  
  CONCLUSIONS
  An extended DPT protocol increased the effectiveness of the allergy workup in our center without compromising patient satisfaction and safety, and it should be recommended to patients with a history of nonimmediate reaction to β-lactam.
authors.affiliation: Sackler Medical School, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Roy
authors.initials: R
authors.lastname: Ratzon
authors.affiliation: Allergy and Immunology Unit, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Avner
authors.initials: A
authors.lastname: Reshef
authors.affiliation: Sackler Medical School, Tel Aviv University, Tel Aviv, Israel; Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Ori
authors.initials: O
authors.lastname: Efrati
authors.affiliation: Allergy and Immunology Unit, Sheba Medical Center, Tel Hashomer, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Deutch
authors.affiliation: Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Rinat
authors.initials: R
authors.lastname: Forschmidt
authors.affiliation: Sackler Medical School, Tel Aviv University, Tel Aviv, Israel; Endocrinology Institute, Gertner Institute for Epidemiology and Health Policy Research, Endocrinology Institute, Sheba Medical Center, Ramat Gan, Israel.
authors.forename: Tali
authors.initials: T
authors.lastname: Cukierman-Yaffe
authors.affiliation: University of Turin, Turin, Italy; Center for Research in Risk Engineering, New York University School of Engineering, New York, New York.
authors.forename: Ron
authors.initials: R
authors.lastname: Kenett
authors.affiliation: Sackler Medical School, Tel Aviv University, Tel Aviv, Israel; Allergy and Immunology Unit, Sheba Medical Center, Tel Hashomer, Israel; Safra Children's Hospital, Sheba Medical Center, Ramat Gan, Israel. Electronic address: Mona.Kidon@sheba.health.gov.il.
authors.forename: Mona Iancovici
authors.initials: MI
authors.lastname: Kidon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004342:Drug Hypersensitivity / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007114:Immunization / Q000379:methods; D007223:Infant; D008297:Male; D008875:Middle Aged; D012882:Skin Tests; D013997:Time Factors; D055815:Young Adult; D047090:beta-Lactams / Q000009:adverse effects / Q000276:immunology*
chemical_list: D047090:beta-Lactams