The results of our study indicate the prevalence of nickel in metal blue-jean buttons to be 16% in the 62 pairs of new and preworn pairs of jeans tested for nickel release with the DMG kit. Variability within the same brand of jeans can be explained both by the duration of wear prior to testing for nickel and by variability in the metal alloys in the blue-jean buttons, even within the same brand of jeans. Notably, there were significantly more new jeans than preworn jeans that tested positive for nickel with the DMG kit. It is possible that over time and with repeated wear, nickel leaches out from the buttons.
Our results differ from a similar survey performed by Byer and Morrell, who tested blue-jean buttons and belt buckles for nickel in local stores with the DMG test. They found that only 10% of 90 pairs of presumably new blue jeans tested positive for nickel and that jeans testing negative for nickel remained negative for nickel with the DMG test even after repeated washings. Our results may indeed suggest a higher prevalence because we tested fewer new jeans than preworn jeans. We also did not test belt buckles in this study, so we cannot compare our results to their results from belt-buckle testing for nickel with the DMG test. It should also be noted that we did not test the snaps or studs of the blue-jean buttons, and since these items are sometimes manufactured separately from the jean buttons, they should be tested with the DMG test.
Patients and physicians should not rely on the DMG test to detect small amounts of nickel that may still be clinically relevant. The sensitivity of the DMG test is variable; in one study, the sensitivity in detecting nickel in earrings was only 25%. The DMG test detects ≥ 10 μg of released nickel, and objects with a nickel release of 0.05 μg can still cause ACD. Thus, the DMG test cannot be considered reliable for detecting smaller amounts of nickel release although it remains a very easy and practical means for patients to monitor nickel release.
It is intriguing that all 10 pairs of jeans that tested positive for nickel by DMG testing were rendered negative by the application of one coat of clear nail polish and that 7 of 7 pairs of jeans were persistently negative through two wash cycles. However, patients typically wash their clothes under more stringent conditions than our test conditions in this study, and the durability of the nail polish coat under repeated washes in the regular cycle is likely to wane. Although the results of our testing were interesting, in clinical practice, we would recommend that patients test for nickel with the DMG test after every wash and that they re-apply the nail polish as indicated. For those patients with nickel-associated ACD who strongly desire to wear blue jeans, an application of clear nail polish may allow them to avoid the allergic sequelae from contact with nickel-containing metal buttons. It would be necessary to simulate increased friction, temperature, and perspiration in patients with documented nickel ACD to see if the application of nail polish could withstand these factors, which are known to amplify nickel ACD.
Despite the anecdotal experience with its use in preventing ACD, surprisingly little has been written about nail polish in the literature. One study that may be partly responsible for the persistence of this clinical application of nail polish is by Moseley and Allen, who used polyurethane on various metallic objects in 11 patients with ACD from nickel and completely prevented ACD in 8 of the 11 patients. The efficacy of the polyurethane coating was limited by peeling of the polyurethane film layer from the metallic object.
Concern exists regarding the potential for a contact dermatitis from nail polish, which our study was not designed to detect. Notably, an estimated 1 to 3% of the population has a nail polish allergy. The most common allergens in nail polish are formaldehyde and toluenesulfonamide formaldehyde resin (TSFR), and one study showed that both are commonly present in numerous nail polishes in sufficient amounts to cause primary sensitization as well as contact dermatitis in patients. Reports in the literature describe patients who developed hypersensitivity to TSFR derived from nail polish.[14,15] Thus, patients and clinicians should be aware of the potential for contact dermatitis in the use of nail polish as a barrier against nickel dermatitis; however, the incidence is unclear. In this study, we used one toluene- and formaldehyde-free nail polish that was not specifically hypoallergenic, so although we would have theoretically avoided sensitizing patients with this particular nail polish preparation, we could not rule out the possibility of eliciting a contact dermatitis with this preparation. In a future study, testing an array of different nail polish preparations, including a hypoallergenic option, would be helpful in detecting whether different preparations are more likely to cause a contact dermatitis.
Prevention of nickel ACD entails avoidance of nickel contact. However, many patients may find avoiding nickel to be difficult. Overall, there are few quality studies on the prevention of nickel-associated ACD. Wohrl and colleagues conducted a blinded controlled trial using diethylenetriamine pentaacetic acid (DTPA) to chelate nickel in 45 patients with nickel allergy. DTPA was effective in preventing and attenuating nickel allergy in patch testing in patients with positive results on prior patch tests with nickel; however, methodological concerns make this study difficult to interpret. The application of pentoxifylline cream prior to exposure to nickel has been shown to have no benefit. Kuzmina and colleagues found no benefit with a urea-containing emollient used as a barrier in preventing skin reactivity when patch-testing nickel-sensitized patients. On the other hand, Ginkgo biloba extract combined with carboxymethyl-β-1,3-glucan formulation, when used as a barrier cream, did significantly reduce skin reactivity in one small double-blind placebo-controlled study, but larger studies of this agent are necessary. Thus, there is a dearth of compelling options for preventing nickel ACD at this juncture.
Dermatitis. 2007;18(4):208-211. © 2007 American Contact Dermatitis Society
Cite this: Blue-Jean Button Nickel: Prevalence and Prevention of Its Release From Buttons - Medscape - Dec 01, 2007.