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 μg/l of serum or urine). Ni was greatly augmented in urine and serum 4 h after the challenge (25th–75th percentiles: 43–264 μg/l urine Ni and 15–52 μg/l serum Ni). 24 h after Ni ingestion, urine Ni was 41–153 μg/l and serum Ni 4–17 μg/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.