Exposure of nickel in used and unused gold-plated earrings: a study using scanning electron microscopy and X-ray microanalysis.

Nickel is the most common contact sensitizer in the female population. The aim of the present study was to examine closely the surface of both used and unused gold-plated earrings by scanning electron microscopy, and to ascertain the distribution of nickel on the surface of these earrings qualitatively and quantitatively by X-ray microanalysis. The claps of 4 sets of used earrings causing nickel dermatitis and of the 3 sets of unused earrings were examined. In backscattered electron images obtained by scanning electron microscopy, a large number of scratches and pits were found on the surface of the used earrings. Cross-sections of the surfaces confirmed that the gold plating was defective in some areas, exposing the nickel. Nickel was readily detected and quantitatively determined in the scratches and pits by X-ray microanalysis. We also found that, even in unused earrings, numerous scratch marks and pits were present, again exposing the nickel. Clearly, even in unused earrings, nickel exposed at the surface sensitizes the skin and causes contact dermatitis.