PracticeUpdate: Dermatology - Winter 2018

EDITOR’S PICKS 14

Prevalence of Contact Allergy to Metals in the European General Population With a Focus on Nickel and Piercings Contact Dermatitis Take-home message • The EDEN Fragrance Study randomly selected a group of 3119 people aged 18 to 74 years from five European countries to undergo patch testing. This current study evaluated the prevalence of nickel allergy and its association with age, gender, nationality, and number of piercings. Overall, females had the higher prevalence of nickel allergy (22.0%). Of the countries represented, Sweden had the lowest prevalence (2.9%), likely reflecting the country’s early institution of laws regulating the nickel content of jewelry. Likewise, younger women were less likely to have a nickel allergy compared with those 31 to 45 years of age and 46 to 60 years old, possibly due to more recent regulation of jewelry nickel content across the rest of Europe. Nickel allergy was positively correlated with number of piercings, with a prevalence of 27.6% in those individuals who had three or more piercings versus 6.4% in those who never had a piercing. • The prevalence of nickel allergy correlates positively with number of piercings; however, rates of nickel sensitization seem to be declining with stricter regulation of jewelry nickel content across Europe. Caitlyn T. Reed MD

Abstract BACKGROUND Studies on sensitization to metals in the general population are scarce. OBJECTIVES To determine the prevalence of sen- sitization to metals in the general population, and factors associated with nickel sensitization. METHODS In 5 European countries (The Nether- lands, Germany, Italy, Portugal and Sweden), a random sample (N =3119) from the general pop- ulation (aged 18-74years) was patch tested and interviewed by use of a questionnaire on expo- sure to metals, piercing, and jewellery. RESULTS Overall, the age-standardized prev- alences of sensitization to nickel, cobalt and chromium were, respectively, 14.5%, 2.1%, and 0.8%. The highest prevalence of nickel sensitiza- tion was seen in Portugal (18.5%) and the lowest (8.3%) in Sweden. The prevalence of cobalt sensitization varied between 3.8% (The Neth- erlands) and 0.9% (Italy), and the prevalence of chromium sensitization varied between 1.3% (Portugal) and 0.2% (Sweden). Significant asso- ciations were observed between nickel allergy and female sex (odds ratio [OR] 5.19; 95% confi- dence interval [95%CI]: 3.99-6.74), past piercing use (OR 3.86; 95%CI: 2.85-5.24), and currently having ≥3 piercings (OR 5.58; 95%CI: 4.02-7.76). CONCLUSIONS The prevalence of sensitization to metals in the European general population was high, mostly because of nickel. The lowest prev- alence of contact allergy to nickel and chromium observed in Sweden supports the effectiveness of long-standing regulation. Prevalence of Contact Allergy to Metals in the European General Population With a Focus on Nickel and Piercings: The EDEN Fra- grance Study. Contact Derm 2018 Jul 01;79(1)1-9, MLA Schuttelaar, RF Ofenloch, M Bruze, et al. www.practiceupdate.com/c/69477

COMMENT By Christen Maria Mowad MD

N ickel is the most common allergen to cause allergic contact dermatitis on patch testing. This study sought to determine the prevalence of allergy to nickel, cobalt, and chromium in the general population in Europe. The researchers found that nickel allergy was the most prevalent, at 14.5%, followed by cobalt at 2.1% and chromium 0.8%. Nickel allergy more commonly affected female patients and was associated with past piercings and multiple piercings (>3). Variations in metal allergy were significant across different countries. Nickel allergy was lowest in Sweden, which adopted the EU nickel directive earlier than other European countries. Nickel regu- lation limits the amount of nickel permitted in products that come into direct contact with the skin. Younger, versus older, women also had a lower rate of sensitization, likely due to the nickel directive being implemented. As nickel allergy remains high in the United States, we could learn from our European colleagues by instituting limits on nickel exposure in this country as well.

PRACTICEUPDATE DERMATOLOGY