Interaction of metals in nickel-sensitive patients.

Nickel (Ni) dermatitis is thought to involve the formation of complexes between Ni ions and suitable proteins. 4 groups of 30 subjects who gave positive patch test responses to NiSO4 2.9% aq. were each retested to 1 of 4 different solutions containing equimolar (0.1 M) amounts of NiSO4 plus MgSO4, NiSO4 plus CuSO4, NiSO4 plus ZnSO4, and NiSO4 plus Li2SO4, respectively. The results, evaluated at 2 days by visual scoring only, demonstrated that the 4 metals exerted a different influence on the nickel reactions, perhaps interfering with one or more factors affecting the formation of Ni+ + complexes.