DISTRIBUTION OF NICKEL AND COBALT FOLLOWING DERMAL AND SYSTEMIC ADMINISTRATION WITH IN-VITRO AND IN-VIVO STUDIES

Contact dermatitis following skin contact with ionic metals occurs in about 15% of the human population, but systemic responses are not as c ommon. It is generally believed that skin contact with metal ions lead s to different biological processing compared with systemic contact. T he purpose of the experiments presented here was to examine eliminatio n of nickel and cobalt salts following skin application and following injection into the deep tissue of hamsters. Ln addition uptake of the metal by fibroblasts and by keratinocytes was examined in vitro. The d ata indicate that elimination of nickel and cobalt in the urine follow ing systemic injection was rapid, as expected, but that elimination fo llowing skin application was delayed. Much of the metal was retained i n the skin. Uptake of the metal by keratinocytes at low doses was grea ter than the uptake by the fibroblasts. At high doses the differences were not as great. Thus the conclusion is drawn that metal salts are r etained in the skin for an extended period of time and could lead to p rolonged antigen processing and consequent immune responses in the der mal tissue. Skin application leads to some systemic distribution but t he systemic application did not lead to skin accumulation. (C) 1996 Jo hn Wiley & Sons, Inc.