Nickel dermatitis: how much nickel is safe?

The Nickel Directive will become law in the countries of the European Union in 1996. This directive states that the concentration of nickel in post assemblies (used after ear piercing) may not exceed 0.05%, that products which come into direct and prolonged contact with the skin, e.g. earrings, watchstraps or zippers, may not release greater than 0.5 microgram/cm2/week, and that nickel release from coated products will not exceed this level after 2 years of normal use. The data relating to the threshold for reacting to nickel and the levels of nickel release from nickel-containing objects, are considered in this review. Although the level of 0.5 microgram/cm2/week is one below which a minority of nickel-allergic subjects will react, it is not safe in every nickel-sensitive individual. This level of nickel release is currently exceeded by many nickel-containing alloys and jewelery items that are made from high-sulfur stainless steel, and manufacturers are going to have to change the composition of jewelery to comply with the directive.