Short contact with nickel causes allergic contact dermatitis: an experimental study.

Summary: Background: Knowledge about the required duration of exposure for elicitation of allergic nickel dermatitis in nickel‐allergic individuals is limited. However, it often has been proposed that short skin contact is safe. Objectives: To examine whether repeated skin contact with nickel over short time periods (3 × 10 min) can elicit allergic nickel dermatitis. Methods: Sixteen nickel‐allergic adults and 10 controls were exposed to, respectively, nickel‐ and aluminium‐containing discs on each volar forearm and on each earlobe for 3 × 10 min. One arm was pretreated for 24 h with sodium lauryl sulfate (SLS) 0·5% under occlusion before exposure. One aluminium and one nickel exposure site were clinically evaluated, and blood flow was measured with laser Doppler flowmetry at day 2 and day 4. Results: Ten of 16 (63%) nickel‐allergic participants developed allergic nickel dermatitis on SLS‐pretreated arm skin and three of 16 (19%) developed it on normal skin on the earlobe. On the SLS‐pretreated arms of nickel‐allergic participants, blood flow increased significantly more on the nickel‐exposed skin than on the aluminium‐exposed skin on days 2 and 4. No change in clinical reactivity or blood flow was found on normal forearm skin in nickel‐allergic participants or on any skin in controls. Conclusions: This experimental study showed that relatively short repeated skin contact (3 × 10 min) with metallic nickel elicits allergic nickel dermatitis in irritated skin and at sites with previous dermatitis. The results support the restrictions in current nickel regulation. What's already known about this topic? Repeated low‐dose nickel exposure may be a more potent trigger of allergic nickel dermatitis than less frequent exposure to a higher single dose.High nickel deposition onto skin can be measured after only seconds of direct skin contact.An impaired skin barrier may increase the risk of allergic nickel dermatitis. What does this study add? Relatively short repeated skin contact (3 × 10 min) with nickel has the potential to provoke allergic nickel dermatitis in irritated skin and at sites with previous dermatitis. Respond to this article Plain language summary available online [ABSTRACT FROM AUTHOR]