title: Leather Contains Cobalt and Poses a Risk of Allergic Contact Dermatitis: Cobalt Indicator Solution and X-ray Florescence Spectrometry as Screening Tests.
abstract: BACKGROUND
  Cobalt was recently identified in a leather couch responsible for dermatitis. Cobalt content/release in leather in the United States is unknown. We evaluated leather for cobalt content/release and investigated screening methods for identifying cobalt in leather.
  
  
  METHODS
  One hundred thirty-one leather swatches were screened for cobalt content/release with X-ray fluorescence (XRF) spectrometry and cobalt indicator solution (CIS). Samples with positive screens and 1 negative control were analyzed using inductively-coupled plasma mass spectrometry (ICPMS).
  
  
  RESULTS
  CIS showed that 5 of 131 samples contained cobalt, subsequently found to be between 1 and 190 parts per million (ppm) when evaluated with ICPMS. The XRF analysis showed that 6 samples contained >5% cobalt, subsequently found to contain greater than 300 ppm cobalt by ICPMS. 7 of 12 tested swatches contained cobalt in excess of 100 ppm. One sample contained greater than 1000 ppm cobalt. The prevalence of swatches containing cobalt at levels in excess of 190 ppm was at least 5% (n = 7; total, N = 131).
  
  
  CONCLUSIONS
  Some leather consumer goods contain and release cobalt. Cobalt indicator solution is a poor screening test for cobalt in leather while XRF screening may be effective. Leather is a new source of cobalt exposure. Exposures to metal allergens are changing in ways that impact clinical decision making.
authors.affiliation: From the *Division of Dermatology, Department of Internal Medicine, The Ohio State University, Columbus; †Loma Linda University School of Medicine, CA; ‡College of Medicine, University of Arizona, Phoenix; and §Department of Dermato-Allergology, National Allergy Research Centre, Copenhagen University Hospital Gentofte, Hellerup, Denmark.
authors.forename: Dathan
authors.initials: D
authors.lastname: Hamann
authors.forename: Carsten R
authors.initials: CR
authors.lastname: Hamann
authors.forename: Patrick
authors.initials: P
authors.lastname: Kishi
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.forename: Jeanne D
authors.initials: JD
authors.lastname: Johansen
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
mesh_terms: D003035:Cobalt / Q000009:adverse effects / Q000032:analysis*; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D006801:Humans; D007202:Indicators and Reagents; D007374:Interior Design and Furnishings; D008403:Mass Screening; D013052:Spectrometry, X-Ray Emission
chemical_list: D007202:Indicators and Reagents; D003035:Cobalt