Oxidative Properties of Skin Exudates – A Determinant for Nickel Diffusion: A Review

Abstract

Skin exudates can corrode (oxidize) and possibly dissolve metal surfaces they contact. Their composition varies as a function of physical, pharmacological and environmental conditions, gender, age, sweat rate, body site and methods of collection, also in a healthy organism. This overview includes sweat composition and discusses components which constitute the skin’s acid mantle: low-molecular-weight acids in sweat and fatty acids in sebum, with a particular potential to solubilize nickel-containing metal objects contacting skin. These components can form nickel salts whose molecular characteristics will determine the preferred route of penetration: either appendageal diffusion or through the intercellular lipid domains, besides the commonly assumed transcellular path. Considering the ease with which elicitation reactions set in when sensitized individuals contact nickel-releasing metal objects, these two alternatives appear to represent pathways which are more likely routes than the conventional transcellular diffusion, which takes a longer time to occur.

Nickel Susceptibility and Skin Barrier Function to Water after Treatment with a Urea-Containing Moisturizer

“…0.1%) [55] . However, the appendages may serve for rapid passage of hydrophilic salts as an early-stage event, although the intercellular pathway becomes dominant for the majority of substances, including water, after reaching steady state [55,56] . Thus, for substances that penetrate the bulk stratum corneum very slowly, these shunt pathways can be signifi cant [57] .…”

Flux of a Nickel(II) Salt versus a Nickel(II) Soap across Human Skin in vitro

“…In earlier work, the flux values for a number of nickel salts through human skin in vivo and in vitro pointed to increasing diffusivity through the SC with decreasing polarity of the compound [8]. Also, micronized metallic nickel applied to the skin under occlusion appeared to steadily penetrate the SC, presumably in the form of a derivative formed by oxidation of the metal in contact with skin exudates [9]. This led to the assumption that the preferred diffusion path for Ni(II) was intercellular via the lipid multilamellar region surrounding the corneocytes.…”