Characteristics of nickel-allergic dermatitis patients seen in private dermatology clinics in Denmark: a questionnaire study.

The use of nickel in certain consumer goods has been regulated in Denmark since 1990. The aim of this study was to reveal the clinical characteristics of nickel-allergic patients seen in seven private dermatology clinics and to identify current sources of nickel that may elicit nickel dermatitis. During 2006 to 2007, 634 patients with dermatitis aged 17-91 years were patch-tested and completed a questionnaire including a question about the occurrence of dermatitis following skin contact with ear-rings or ear-pins, watches, buttons or metal clasps (i.e. metal dermatitis). chi2 tests were applied to test for statistical significant differences. Analysis revealed a lower prevalence of nickel allergy among women in the youngest age group (17-22 years) in comparison with older age groups (23-34 years and 35-46 years) (p < 0.03). Most patients experienced metal dermatitis on the first occurrence be-tween 1975 and 1985. No new cases of metal dermatitis were identified after 1985. We conclude that nickel allergy has decreased among young females with dermatitis due to the nickel regulation.