Effects of repeated skin exposure to low nickel concentrations: a model for allergic contact dermatitis to nickel on the hands

We studied the effects of repeated daily exposure to low nickel concentrati ons on the hands of patients with hand eczema and nickel allergy. The conce ntrations used were chosen to represent the range of trace to moderate occu pational nickel exposure. The study was double-blinded and placebo controll ed. Patients immersed a finger for 10 min daily into a 10-p.p.m, nickel con centration in water for the first week, and during the second week into a 1 00-p.p.m, nickel concentration. This regimen significantly increased (P = 0 .05) local reside formation and blood flow (P = 0.03) as compared with a gr oup of patients who immersed a finger into water. The nickel concentrations used also provoked significant inflammatory skin changes on sodium lauryl sulphate (SLS)-treated forearm skin of the patients, whereas inflammatory s kin changes a ere not observed in healthy volunteers without hand eczema an d nickel allergy, either on normal or on SLS-treated forearm skin. The pres ent study strongly suggests that the changes observed were specific to nick el exposure, Standardized methods to assess trace to moderate nickel exposu re on the hands, and the associated effects in nickel-sensitized subjects, are needed.