Nickel-Directed US Health Policy
The incidence of nickel-induced allergic contact dermatitis is rising. In the 1990s, the European Union passed the Nickel Directive limiting the weekly allowable release of nickel from products. However, similar legislation has yet to be adopted in the United States. This article reviews the burden of nickel sensitivity and initiatives in place to combat this growing problem.
As early as the 1600s, a dark red ore with a distinct green coating became a notable source of irritation for copper miners in Saxony, Germany.1 Believing that the dark red substance was an ore of copper, they continued mining it. As the ore was causing ailments, the miners turned to folklore and adopted a belief that it was protected by goblins. This ultimately led to the naming of the ore as “kupfernickel,” translating to “goblin’s copper.”1 It was not until the mid-1750s, that Swedish chemist Axel Cronstedt discovered the true nature of kupfernickel (nickel arsenide) and through experiments on magnetism realized the isolation of a new element.1 Since then, because of its relatively low cost and unique properties such as malleability and anticorrosive nature, nickel has been used in a large variety of fields.
After World War II, nickel was commonly included in costume jewelry. Jewelry and piercings have thereafter become major sources of nickel exposure for the general population, and thus, a major source for nickel sensitization. Interestingly, meteorites are one of the principal sources of nickel in the world. Metal bead artifact-jewelry made from meteorites has been found in Egyptian graves dating back to as early as 5000 BC, and wedding rings made from the 1836 Namibian Gibeon-meteorite have been reported to cause nickel allergic contact dermatitis (ACD).2 The common practice of jewelry use in females among various cultural groups around the world has resulted in a much higher rate of nickel sensitization among females than males.3
In 1981, Peltonen wrote a commentary about the problem of nickel sensitivity4 in which she described the significant importance of nickel over the prior 20 to 30 years, now — 34 years later, nickel is still ranking first in the list of allergens.5 Peltonen noted that nickel sensitivity was surprisingly common among the US population as gathered through epidemiologic studies.4 In 1978, 1,158 volunteers were tested with 2.5% nickel sulfate in order to find the underlying prevalence of nickel sensitivity.6 The study found that 9% of the subjects were sensitized6 — by recent counts, that number has almost tripled.7 Additionally, Peltonen reported the significant association between atopy, nickel sensitivity and hand eczema. Some patients with an underlying nickel dermatitis do not present in a clinically obvious fashion, but rather with hand or other types of eczema.4 In fact, nickel sensitivity is a much wider problem as Peltonen alarmingly and poignantly pointed out over 30 years ago: “half of the subjects sensitized to nickel have never consulted a doctor because of their nickel dermatitis; still fewer have visited a dermatologist.”4
The Hidden Nickel Dermatitis
While nickel dermatitis is commonly associated with a localized reaction, as many as 50% of children with nickel-induced ACD can present with more diffuse reactions — known as idiopathic. Clinically, idiopathic nickel dermatitis appears as pruritic papules in non-exposed sites, such as on the extremities and upper trunk.8 In the idiopathic-type of response, areas that may not in fact have had direct contact with nickel can potentially generate a response secondary to autosensitization from immune cells circulating in the body.9 Unfortunately, as discussed, this type of a reaction has the potential to be misdiagnosed as an eczema (such as atopic dermatitis [AD]), due to its diffuse nature and its common involvement of the upper arms, thighs, knees and elbows.10 Furthermore, as a side note, “children with AD may experience an exacerbation of their atopic pruritus secondary to comorbid nickel ACD.”8 Recent evidence indicates that patients with AD have a genetic mutation that allows nickel to more easily penetrate the upper epidermis allowing easier exposure to the immune system.11 At this time, we do not know the number of children who suffer from nickel dermatitis, and are placed on systemic immunosuppressive therapy for what is thought to be “atopic disease,” rather than being accurately identified and treated with allergen avoidance for ACD. As Peltonen so clearly articulated over 30 years ago, large population studies, including those cases never seen at dermatologic clinics, are needed.
Although there are products available to test various materials for nickel, the source of nickel ACD is often obvious; for example, neck or earlobe dermatitis from use of costume jewelry, the periumbilical area from contact with a belt buckle or pants snap, or the unilateral facial dermatitis from the cellular phone8,12 (Table). With the rising nickel sensitization and ACD, the Danish Ministry of the Environment passed legislation in 1992 to regulate the amount of nickel released from products with prolonged skin contact in an effort to decrease the rates of sensitization to nickel.13 This limitation on nickel release to less than 0.5 µg/cm2 per week helped to decrease rates of sensitization among Danish children age 0 to 18 years from 24.8% to 9.2% between 1985 and 1998, respectively.14 In 1994, the European Union (EU) recognized this dramatic decrease in morbidity and enacted the Nickel Directive legislation. This legislation limited the weekly allowable release of nickel to less than 0.5 µg/cm2. A 2004 amendment further reduced the weekly allowable release of nickel from [earring (piercing)] posts placed after piercing to 0.02 µg/cm2.15 These initiatives have not only resulted in decreases in sensitization rates, but have greatly reduced both the indirect and direct societal costs of nickel dermatitis — saving a reported $2 billion US dollars over a 20-year period.15-17 Nevertheless, nickel ACD continues to be problematic even in the EU as increasing numbers of recognized cases in younger children without a history of piercing continue to be reported.18 Thus, other sources of nickel exposures need to be investigated and ultimately reductions of exposure in a broader scope may be necessary. Moreover, analyses of the mechanisms for and timing of nickel release from metals may provide more information on certain safer materials or practices for nickel-containing items.
The State of Regulation in the United States
Despite regulations in Europe with proven clinical outcome success, similar legislation has yet to be adopted in the United States, even in the face of similar nickel sensitization rates to those seen in Europe in the mid-1980s.3 For example, the most recent North American Contact Dermatitis Group (NACDG) 2005-2012 data demonstrates that 25.6% of 883 children patch tested had a clinically relevant response to nickel.3 In order to prevent early exposure to nickel and consequently decrease the rates of nickel contact allergy, US initiatives are needed to limit the quantity of nickel released from products with prolonged skin contact. “Approximately 10 years ago, representatives from the Nickel Development Institute and the Nickel Producers Environmental Research Association met with the Consumer Product Safety Commission (CSPC) urging the US adoption of legislation similar to the 1994 European Nickel Directive, which is now included in the Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals.”18 In fact “The CPSC shared concerns over the need for limiting nickel release from articles that would come in direct and prolonged contact with the skin, but could not commit to action at that time.”18 Thus, the US not only lacks legislation regulating prevalent products such as piercing equipment and jewelry posts, but also common children-directed merchandise and clothing.19 In a recent study, Jensen et al indicated that over half the toys containing metal in the US contain nickel.18 Furthermore, there are increasing reports of potential sources of nickel in cell phones, iPads, laptops and other electronic devices, including the rapidly expanding market of portable wearable health-oriented computing devices.20-22
In 2009, the Journal of the American Academy of Dermatology published an article on the need for an EU-like Nickel Directive to limit the maximum allowable release of nickel from products with prolonged skin contact in the United States, consistent with the concentrations mandated in Europe.23 Based on the fact that approximately 35.8% of the North American patch-test female patients under the age of 18 were reported to have nickel contact allergy in the United States,7 the authors discussed that a Nickel Directive in the United States could dramatically lower the burden of ACD from nickel both through national legislation and public health education.23 Nevertheless, since nickel cases are widely underreported and potentially remain undiagnosed, a better definition of the hidden nickel epidemic must exist in order to have an accurate “before and after” understanding of the population in the context of any governmental legislation.
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