Patch test reactivity to nickel alloys

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.