title: A novel phenotype of nonsteroidal anti-inflammatory drug hypersensitivity: the high-risk patient.
abstract: BACKGROUND
  : Some nonsteroidal anti-inflammatory drug (NSAID)-hypersensitive patients develop adverse reactions when challenged with weak cyclooxygenase 1 (COX-1) inhibitors.
  
  
  OBJECTIVE
  : To investigate the prevalence and clinical features of this high-risk population.
  
  
  METHODS
  : Patients from 2 outpatient allergy clinics consulting between October 2005 and October 2007 because of adverse reactions to classic NSAIDs were submitted to confirmatory double-blind oral challenges with the suspected NSAID and with acetaminophen, preferential and/or specific COX-2 inhibitors. Patients were then classified as low-risk and high-risk groups according to the results of provocation tests.
  
  
  RESULTS
  : Three hundred three patients were studied: 179 (59.0%) were tolerant to acetaminophen and the selective COX-2 inhibitors (low-risk group), whereas 124 (40.9%) developed reactions to at least one of the "low COX-1 inhibitors" (high-risk group). No distinctive demographic or clinical characteristics were present when both groups of patients were compared.
  
  
  CONCLUSIONS
  : A large proportion of patients sensitive to classic NSAIDs cannot tolerate the weak COX-1 inhibitors. Oral challenges should be performed by trained specialists to advise these patients about the use of NSAIDs.
authors.affiliation: From the 1Allergy Department, Clínica El Avila; 2Allergy and Immunology Department, Centro Médico-Docente La Trinidad; and 3Allergy Department, Centro Médico de Caracas, Caracas, Venezuela.
authors.forename: Mario
authors.initials: M
authors.lastname: Sánchez-Borges
authors.forename: Arnaldo
authors.initials: A
authors.lastname: Capriles-Hulett
authors.forename: Fernan
authors.initials: F
authors.lastname: Caballero-Fonseca