title: Use of ketoprofen oral challenges to detect cross-reactors among patients with a history of aspirin-induced urticaria.
abstract: BACKGROUND
  In patients with a history of urticaria induced by a single nonsteroidal anti-inflammatory drug (NSAID), advising elimination of all drugs that inhibit cyclooxygenase 1 (COX-1) can lead to unnecessary avoidance of useful NSAIDs.
  
  
  OBJECTIVE
  To classify patients with a history of aspirin-induced urticaria as cross-reactors or single-drug reactors by oral challenges with another strong COX-1 inhibitor, namely, ketoprofen.
  
  
  METHODS
  Forty otherwise healthy patients with a history of acute urticaria after the ingestion of aspirin underwent single-blind, placebo-controlled oral challenges with ketoprofen. In patients who did not tolerate ketoprofen, tolerance tests with drugs exerting either COX-1 inhibition at high doses (acetaminophen and nimesulide) or no COX-1 inhibition at therapeutic doses (rofecoxib and tramadol) were performed.
  
  
  RESULTS
  In 24 patients (60%), ketoprofen induced urticaria that was controlled by an intravenous antihistamine; 18 (75%) of the 24 patients reacted after the first provocative dose. On subsequent challenges, 3 (38%) of 8 ketoprofen reactors did not tolerate nimesulide, whereas acetaminophen tramadol and rofecoxib were tolerated by 18 of 18, 14 of 14, and 16 of 16 ketoprofen reactors, respectively. Three ketoprofen reactors reported the onset of spontaneous recurrent urticaria 1 to 3 years after the challenge tests.
  
  
  CONCLUSIONS
  In patients with a history of urticaria induced by a single NSAID, oral challenges with alternative COX-1 inhibitors are helpful in detecting whether they are true single-NSAID reactors; weak COX-1 inhibitors should be challenged subsequently only in those who show multiple-NSAID intolerance.
authors.affiliation: Ambulatorio di Allergologia, Clinica San Carlo, Paderno Dugnano (MI), Italy. r.asero@libero.it
authors.forename: Riccardo
authors.initials: R
authors.lastname: Asero
mesh_terms: D000082:Acetaminophen / Q000009:adverse effects; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects; D001241:Aspirin / Q000009:adverse effects*; D003429:Cross Reactions; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D004342:Drug Hypersensitivity / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007660:Ketoprofen / Q000008:administration & dosage* / Q000009:adverse effects; D007783:Lactones / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D010919:Placebos; D013449:Sulfonamides / Q000009:adverse effects; D013450:Sulfones / Q000009:adverse effects; D014147:Tramadol / Q000009:adverse effects; D014581:Urticaria / Q000139:chemically induced*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D007783:Lactones; D010919:Placebos; D013449:Sulfonamides; D013450:Sulfones; C116926:rofecoxib; D000082:Acetaminophen; D014147:Tramadol; D007660:Ketoprofen; D001241:Aspirin; C012655:nimesulide