An arm immersion model of compromised skin (II). Influence on minimal eliciting patch test concentrations of nickel.

The transition metal nickel is a very common cause of allergic contact dermatitis (ACD). In the general population, adults with hand eczema have a high incidence of allergy to nickel, and nickel allergy is high in occupational dermatoses and is often linked to wet work. Nickel may be found as a trace contaminant in some consumer products, e.g., household cleaning agents. It has therefore been debated whether these levels, whilst not a primary cause, might be sufficient to maintain ACD. The minimal concentration of nickel in patch tests on normal skin that will elicit an allergic reaction in highly sensitised subjects is 1-10 ppm. This trial assessed whether reactivity to nickel was altered on compromised dorsal forearm skin and compared this to normal skin on the contralateral dorsal forearm and on the back. Skin damage consequent upon arm immersion in sodium dodecyl sulphate (SDS) greatly enhanced reactivity to nickel on the forearm, with the dorsal aspect reacting most both in number of reactions at each concentration and in the minimal eliciting concentration, which was 0.5 ppm in 2/20 under the conditions of a 48 h occluded patch.