title: Usage test with palladium-coated earrings in patients with contact allergy to palladium and nickel.
abstract: BACKGROUND
  Since the EU Nickel Directive came into force, concern has been raised that palladium may increasingly replace nickel in alloys used in jewellery and dentistry, and that it may cause as many allergy problems as nickel.
  
  
  OBJECTIVE
  (i) To investigate the clinical relevance of contact allergy to palladium resulting from the wearing of palladium-coated earrings, and (ii) to evaluate the concordance in test results between palladium chloride (PdCl2 ), sodium tetrachloropalladate (Na2 PdCl4 ), and nickel(II) sulfate hexahydrate (NiSO4 .6H2 O), as well as variability in patch test reactivity.
  
  
  METHODS
  Forty female patients with pierced earlobes and previously known contact allergy to palladium and nickel were patch tested with dilution series of nickel and palladium salts. They wore earrings covered with palladium and titanium for 9 weeks to monitor the appearance of any clinical manifestations.
  
  
  CONCLUSIONS
  There is a low risk of eczema in palladium-allergic and nickel-allergic individuals when they wear jewellery coated with pure palladium, but further studies are needed to determine whether palladium, when present in alloys, could cause allergic reactions. PdCl2 , like NiSO4 .6H2 O, shows variability in patch test reactivity over time. Furthermore, Na2 PdCl4 seems to be a more sensitive test substance than PdCl2 for the detection of palladium allergy.
authors.affiliation: Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, Malmö, S-205 02, Sweden,; Department of Dermatology, Skåne University Hospital, Lund University, Malmö, S-205 02, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Tillman
authors.forename: Malin
authors.initials: M
authors.lastname: Engfeldt
authors.forename: Monica
authors.initials: M
authors.lastname: Hindsén
authors.forename: Magnus
authors.initials: M
authors.lastname: Bruze
mesh_terms: D000485:Allergens / Q000008:administration & dosage; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D005260:Female; D006801:Humans; D055498:Jewelry / Q000009:adverse effects*; D009532:Nickel / Q000008:administration & dosage; D010165:Palladium / Q000008:administration & dosage / Q000009:adverse effects*; D010328:Patch Tests / Q000379:methods*; D011446:Prospective Studies; D018570:Risk Assessment
chemical_list: D000485:Allergens; C030174:tetrachloropalladium; C029938:nickel sulfate; D010165:Palladium; D009532:Nickel; C008756:palladium chloride
keywords: contact allergy; jewellery; nickel; palladium; patch test reactivity; sodium tetrachloropalladate; variability