title: Full-course drug challenge test in the diagnosis of delayed allergic reactions to penicillin.
abstract: BACKGROUND
  Drug challenge test (DCT) has long been the most sensitive test in the allergological work-up when investigating for penicillin allergy.
  
  
  OBJECTIVE
  To improve sensitivity of the diagnostic work-up in diagnosing penicillin allergics with histories of allergic reactions on day 2 or later in the course of penicillin treatment.
  
  
  METHODS
  A full-course DCT was added to the current protocol if specific IgE, skin tests and DCT were all negative in patients who had a nonimmediate reaction to penicillin treatment. Sixteen patients with a history of an immediate reaction to penicillin treatment underwent testing with negative outcomes.
  
  
  RESULTS
  Fifty percent of patients undergoing full-course DCT experienced a cutaneous adverse drug reaction. None of the controls reacted (p = 0.001). The mean time of reaction was 6 days. Penicillin V accounted for most reactions. Urticaria was the most frequent clinical reaction observed.
  
  
  CONCLUSIONS
  Full-course DCT offers an improvement of sensitivity and predictive values of the diagnostic work-up of allergic reactions to penicillin occurring on day 2 of penicillin treatment or later.
authors.affiliation: Department of Dermatology, Odense University Hospital, Odense, Denmark. science@skonvirke.dk
authors.forename: Jakob E
authors.initials: JE
authors.lastname: Borch
authors.forename: Carsten
authors.initials: C
authors.lastname: Bindslev-Jensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000009:adverse effects; D004342:Drug Hypersensitivity / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000009:adverse effects*; D012680:Sensitivity and Specificity; D012882:Skin Tests; D014581:Urticaria / Q000209:etiology; D055815:Young Adult
chemical_list: D010406:Penicillins; D007073:Immunoglobulin E; D000658:Amoxicillin