High nickel release from 1- and 2-euro coins: are there practical implications?

To determine the release of nickel from 1- and 2-euro coins and the ability to produce allergic contact dermatitis from the application of coins to the palmar skin of nickel-sensitized individuals. Three experiments were conducted. Experiments 1 and 2 checked the release of nickel from 1- and 2-euro coins by using the dimethylglyoxime test. In experiment 3, the elicitation of positive reactions was checked by applying coins to the palmar skin for 48 h under occlusion in nickel-sensitized and non-sensitized individuals. The dimethylglyoxime test for release of nickel was positive in all cases. Positive patch test reactions to euro coins applied to the palmar skin of nickel-sensitized individuals were observed at 48 and 96 h. The results show that positive patch test reactions to euro coins can be obtained from nickel-sensitized individuals after 48 h of application to the palmar skin under occlusion. These results do not contradict other experiments in which repeated handling of coins was unable to provoke fingertip allergic contact dermatitis. A dose-response relationship is a credible explanation to support such potential discrepancies.