Patch test reactivity to nickel alloys

Abstract

11 widely used nickel alloys were investigated with respect to corrosion stability and reactivity in nickel-sensitive individuals. Alloys with a nickel release in synthetic sweat exceeding 1 microgram/cm2/week gave a strong patch test reaction in nickel-sensitive persons; those with a release below 0.5 microgram/cm2/week showed weak reactivity with one exception. Nickel allergy is a health problem. It may be minimized by using nickel alloys with a corrosion level below 0.5 microgram/cm2/week. Action should be taken by dermatologists, industry and authorities to solve this neglected problem.

Nickel release from earrings purchased in the United States: The San Francisco earring study

“…This indicates the presence of nickel in sufficient concentrations ([0.5 g/cm 2 /wk) to sensitize 22 and elicit nickel dermatitis. 23 DMG also produces a red color when it reacts with ferrous salts whereas the presence of cobalt salts may consume the DMG, reducing the sensitivity of the test. 20 This is mainly important when the amount of nickel is small or the amount of cobalt is large.…”

Contact allergy epidemics and their controls*

“…Based on this research, a limit of 0.5 mg/cm 2 per week of nickel release was suggested and acknowledged as a safe limit for nickel exposure (21). In 1990, a legislation was passed in Denmark to diminish nickel release in consumer products (23).…”

“…Investigations showed that the induction and elicitation of nickel contact allergy depended on the amount of nickel per skin unit area present in the epidermis and on the fact that free nickel ion could be leached out as a response to the corrosion caused by human sweat on nickel-plated surfaces and alloys (20)(21)(22). Based on this research, a limit of 0.5 mg/cm 2 per week of nickel release was suggested and acknowledged as a safe limit for nickel exposure (21).…”

Prevalence of nickel and cobalt allergy among female patients with dermatitis before and after Danish government regulation: A 23-year retrospective study

“…5 This exposure limit was primarily based on results from experimental clinical exposure studies performed in Denmark and Sweden. 6,7 The 1994 European Union (EU) Nickel Directive was extended to prohibit nickel in coated products, unless the coating was sufficient to ensure that the nickel release would not exceed 0.5 g/cm 2 /wk after 2 years of normal use. 8 Finally, a recent amendment restricted the level of permitted nickel release in post assemblies (also called ''studs'' or simply ''posts'') at 0.2 g/cm 2 /wk.…”