US EPA

1236748 

Journal Article 

Studies concerning the sensitizing effect of cobalt 

Valér, M; Somogyi, Z; Racz, I 

1967 

Yes 

Dermatologica
ISSN: 0011-9075 

NIOSH/00137790 

134 

1 

36-50 

English 

4226549 

https://www.karger.com/Article/FullText/254236
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Methods to distinguish true sensitivity to cobalt (7440484) from joint reactions to cobalt and other substances were studied in Hungary. Epicutaneous tests with 1, 2, and 5 percent solutions of cobalt-chloride (7646799) were performed on 1,280 patients. Many were cement workers, and all suffered from occupational skin disease. Tests were also done with varying mixtures and concentrations of cobalt-chloride, a chromate salt, turpentine, and nickel-sulfate (7786814). Hungarian cement was analyzed for chromium (7440473), nickel (7440020), and cobalt content. Intradermal testing for cobalt sensitivity was performed on 47 persons believed sensitive to cobalt, chromium, and nickel. Epicutaneous testing with 2 and 5 percent solutions produced a positive reaction in 44 persons. Correlation with cobalt contact at work could be established in 29.5 percent of these cases. In the other cases, the reaction was considered a nonspecific joint reaction produced by a more potent sensitizer. For example, 15 of 97 persons sensitized to turpentine also showed positive cobalt reactions. A high correlation between a positive intradermal test and the presence of cobalt in the workplace could be established. The authors conclude that cobalt tends to produce pseudospecific epicutaneous tests. The intradermal injection is highly specific and reliable for cobalt sensitization. Criteria for true sensitization to cobalt are a positive intradermal test at a 1 to 1,000 dilution at 72 hours with a cobalt salt no stronger than a 2 percent concentration, and the confirmation or high probability of contact with cobalt, not discounting the possibility of exposure outside the workplace.