A patch test study to evaluate the allergenicity of a metallic jewelry alloy in patients allergic to cobalt.

Cobalt is a common inducer of allergic contact dermatitis. A new jewelry alloy containing cobalt was developed and tested on 30 individuals with documented allergy to cobalt. Of these subjects, 5 (18%) were found to be allergic to the new alloy after 7 or 8 days of exposure. In all cases, the reaction was much less severe than allergy to the 1% cobalt chloride patch test material. This new alloy should be better tolerated by individuals allergic to cobalt, perhaps because the cobalt is tightly bound in the alloy by the other main component, platinum.