Nickel release from ear piercing kits and earrings.

Ear piercing with nickel-alloyed studs/clasps involves considerable risk of nickel sensitisation. Stainless steel studs/clasps for ear piercing and different types of earring were stored in synthetic sweat for 1 week. The nickel release was determined. One "hypoallergenic" stud/clasp released 0.005 microgram Ni; 21 unused studs/clasps and earrings released 0.05-3 microgram Ni, and 11 unused studs/clasps and earrings released 6-25 micrograms Ni. 6 earrings which caused dermatitis released 14-442 micrograms Ni. Thus, all studs/clasps and earrings released nickel. Neither gold nor silver plating prevented the nickel release. Nickel-sensitive women were asked to wear studs/clasps releasing various amounts of nickel. The most sensitive of them showed eczematous reactions to studs/clasps releasing nickel down to 0.05 micrograms. The dimethylglyoxime test was positive only when more than 10 micrograms Ni was released.