title: The cost of nickel allergy: a global investigation of coin composition and nickel and cobalt release.
abstract: BACKGROUND
  Nickel is widely used in coins; nickel may cause contact allergy and allergic contact dermatitis in those who handle them.
  
  
  OBJECTIVE
  To investigate alloy use, coin composition and nickel and cobalt release for a worldwide selection of currently circulating coins.
  
  
  METHODS
  Eight hundred and fifty coins of 361 different denominations or issues from 52 countries were collected and analysed with X-ray fluorescence spectrometry and nickel and cobalt spot tests.
  
  
  RESULTS
  Copper-nickel was the most frequently identified coin alloy, being observed in 100 denominations (28%), followed by aluminium-bronze (62, 17%). In total, 239 denominations released nickel (28%). Coins from Bolivia, Brazil and Costa Rica did not release nickel. Fewer than one-third of the denominations or issues from China, India, the euro area and Indonesia released nickel. In the United States, the Russian Federation, Japan, and Mexico, one-third or more of the denominations released nickel.
  
  
  CONCLUSIONS
  This worldwide selection of circulating coins covered countries with 75% of the world population, and shows that the majority of the world population lives in countries where coins release nickel. Pertinently, ∼ 40% of circulating coin denominations do not release nickel.
authors.affiliation: Loma Linda University School of Medicine, Loma Linda, CA 92350, USA. hamann511@gmail.com
authors.forename: Carsten R
authors.initials: CR
authors.lastname: Hamann
authors.forename: Dathan
authors.initials: D
authors.lastname: Hamann
authors.forename: Curtis
authors.initials: C
authors.lastname: Hamann
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.forename: Carola
authors.initials: C
authors.lastname: Lidén
mesh_terms: D003035:Cobalt / Q000009:adverse effects* / Q000737:chemistry; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D006229:Hand Dermatoses / Q000139:chemically induced*; D006801:Humans; D009532:Nickel / Q000009:adverse effects* / Q000737:chemistry; D009717:Numismatics; D009784:Occupational Diseases / Q000139:chemically induced*; D016273:Occupational Exposure / Q000009:adverse effects*; D010091:Oximes / Q000032:analysis; D012307:Risk Factors; D013052:Spectrometry, X-Ray Emission
chemical_list: D010091:Oximes; C013501:dimethylglyoxime; D003035:Cobalt; D009532:Nickel