Table 1.

Scheme of up dosing and maintenance of nickel oral hyposensitization of the four groups.

Days	Group 1Ni dose	Group 2Ni dose	Group 3Ni dose	Group 4
1–10	1 ng/day	Placebo	Placebo	Placebo
11–20	10 ng/day	1 ng/day	Placebo	Placebo
21–30	0.1 μg/day	10 ng/day	1 ng/day	Placebo
31–40	0.5 μg/day	0.1 μg/day	10 ng/day	Placebo
41–320	0.5 μg 3 times a week	0.1 μg 3 times a week	10 ng 3 times a week	Placebo 3 times a week

All eligible patients after one month of Ni-pour diet were randomly assigned to one of the four groups of treatment. Nickel dose was progressively increased in 40 days from 1 ng to 3 definite maintenance doses (10 ng, 0.1 μg and 0.5 μg) administered 3 times a week for a total of 12 months. In order to protect the blinding, patients randomized to lower doses received placebo during the first days of the up-dosing phase.