Serum and urine nickel in nickel-sensitized women: effects of oral challenge with the metal.

15 women with a positive patch test only to nickel (Ni) and without atopy and 10 control women were selected for the study. Blood and urine specimens were collected with a standard procedure either before (at 8 a.m.) or 4 and 24 h after the ingestion of 10 mg of Ni (as Ni sulfate). 7 of the Ni-sensitized patients showed a flare-up of eczema and/or urticaria during the test, while the other women were non-symptomatic. Serum and urine Ni of controls and Ni-sensitized women did not significantly differ. Serum and urine Ni levels determined before the oral Ni challenge were in the range of reference values recently reported by other authors (0.2-2.0 micrograms/l of serum or urine). Ni was greatly augmented in urine and serum 4 h after the challenge (25th-75th percentiles: 43-264 micrograms/l urine Ni and 15-52 micrograms/l serum Ni). 24 h after Ni ingestion, urine Ni was 41-153 micrograms/l and serum Ni 4-17 micrograms/l. Our study confirms a previous investigation showing similar levels of serum and urine Ni following ingestion of the metal in control and Ni-sensitized women without atopy.