title: Skin test-positive immediate hypersensitivity reaction to iodinated contrast media: the role of controlled challenge testing.
abstract: BACKGROUND
  Immediate hypersensitivity reactions (IHR) to iodinated contrast media (ICM) have traditionally been considered nonallergic; however, the increasingly frequent reporting of positive skin test and basophil activation test results suggests a specific allergic mechanism in some patients. Skin tests have been proposed as a useful tool for diagnosis, although their sensitivity and predictive values remain to be determined. The role of controlled challenge testing has not been assessed.
  
  
  OBJECTIVE
  We aimed to evaluate the role of controlled challenge testing in skin test-positive IHR to ICM.
  
  
  METHODS
  We evaluated 106 patients with IHR to ICM by performing skin tests with the agent that caused the reaction. Patients with a positive result were selected. Skin tests were extended to a series of 8 ICMs; 5 patients underwent controlled challenge test with an alternative skin test-negative ICM; a further 2 patients underwent computed tomography with an alternative skin test-negative ICM. No premedication was administered.
  
  
  RESULTS
  Intradermal test results were positive to the ICM that caused the reaction in 11 out of 106 patients (10.4%). Five of the 11 patients tolerated a controlled challenge test with an alternative skin test-negative ICM. The 2 patients who underwent computed tomography with an alternative skin test-negative ICM tolerated the medium.
  
  
  CONCLUSIONS
  Skin tests are useful for the diagnostic workup in patients with an allergic IHR to ICM. Since ICM cannot be avoided in many patients because they are irreplaceable in some diagnostic or therapeutic techniques, an alternative safe ICM should be investigated for future procedures. We propose the use of controlled challenge tests based on skin test results to address this need in skin test-positive reactions in order to identify an alternative non-cross-reactive ICM.
authors: Allergy Service, Hospital General Universitario Gregorio Marañón, Madrid, Spain. aprieto.hgugm@salud.madrid.org
authors: A
authors: A
authors: Prieto-García
authors: M
authors: M
authors: Tomás
authors: R
authors: R
authors: Pineda
authors: P
authors: P
authors: Tornero
authors: T
authors: T
authors: Herrero
authors: V
authors: V
authors: Fuentes
authors: L
authors: L
authors: Zapatero
authors: M
authors: M
authors: de Barrio
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003287:Contrast Media / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced / Q000175:diagnosis*; D007455:Iodine / Q000009:adverse effects* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012882:Skin Tests; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007455:Iodine