Nickel and cobalt release from jewellery and metal clothing items in Korea

Background In Korea, the prevalence of nickel allergy has shown a sharply increasing trend. Cobalt contact allergy is often associated with concomitant reactions to nickel, and is more common in Korea than in western countries. Objective The aim of the present study was to investigate the prevalence of items that release nickel and cobalt on the Korean market. Materials and methods A total of 471 items that included 193 branded jewellery, 202 non-branded jewellery and 76 metal clothing items were sampled and studied with a dimethylglyoxime (DMG) test and a cobalt spot test to detect nickel and cobalt release, respectively. Results Nickel release was detected in 47.8% of the tested items. The positive rates in the DMG test were 12.4% for the branded jewellery, 70.8% for the non-branded jewellery, and 76.3% for the metal clothing items. Cobalt release was found in 6.2% of items. Among the types of jewellery, belts and hair pins showed higher positive rates in both the DMG test and the cobalt spot test. Conclusion Our study shows that the prevalence of items that release nickel or cobalt among jewellery and metal clothing items is high in Korea.