Prevalence of nickel allergy in Europe following the EU Nickel Directive - a review.

Nickel contact allergy remains a problem in EU countries, despite the EU Nickel Directive. To study the prevalence of nickel allergy in EU countries following the implementation of the EU Nickel Directive, we performed a systematic search in PubMed for studies that examined the prevalence of nickel allergy in EU countries published during 2005-2016. We identified 46 studies: 10 in the general population and 36 in patch tested dermatitis patients. A significantly lower prevalence of nickel allergy after than before the implementation of the EU Nickel Directive was found in women aged 18-35 years (11.4% versus 19.8%) (p = 0.02), in female dermatitis patients aged ≤17 years (14.3% versus 29.2%) (p < 0.0001), and in dermatitis patients aged 18-30 years (women: 20.2% versus 36.6%) (p < 0.0001) (men: 4.9% versus 6.6%) (p < 0.0001). Overall, the prevalence was higher in southern than in northern EU countries, and generally remained high, affecting 8-18% of the general population. A consistent pattern of decreasing prevalence of nickel allergy in some EU countries was observed, although the prevalence among young women remains high. Steps should be taken for better prevention of nickel allergy in EU countries.