Nickel allergy in a Danish population 25 years after the first nickel regulation

Background. Nickel in metallic items has been regulated in Denmark since 1990; however, 10% of young Danish women are still sensitized to nickel. There is a need for continuous surveillance of the effect of regulation. Objectives. To identify current self-reported metallic exposures leading to dermatitis in nickel-allergic patients, and the minimum contact time needed for dermatitis to occur. Methods. A questionnaire was sent to all patients who reacted positively to nickel sulfate 5% pet. within the last 5 years at the Department of Dermatology and Allergy, Gentofte Hospital. Results. The response rate was 63.2%. Earrings were the foremost cause of dermatitis after the EU Nickel Directive had been implemented, followed by other jewellery, buttons on clothing, belt buckles, and wrist watches. Dermatitis reactions within 10 min of contact were reported by 21.4% of patients, and dermatitis reactions within 30 min of contact were reported by 30.7% of patients. Conclusions. Nickel exposures that led to the implementation of a nickel regulation seem to persist. The durations of contact with metallic items to fall under the current REACH regulation of nickel correspond well with the results of this study.