MIAMI BEACH – The risk of nickel and cobalt sensitivity increases in tandem with the number of body piercings, according to findings from a study involving nearly 9,400 patch-tested patients.
Overall, 3,907 (41.6%) of the 9,388 subjects had no piercings, 131 (1.3%) had one piercing, 3,987 (42.5%) had two piercings, 934 (9.9%) had three to four piercings, and 429 (4.6%) had five or more piercings, Jaime L. Loso reported at the annual meeting of the American Contact Dermatitis Society.
Nickel and cobalt sensitivity both were significantly associated with piercing (relative risks of 2.52 and 1.63, respectively); chromate sensitivity had an inverse relationship with piercing (relative risk, 0.60), said Ms. Loso, a third-year medical student at the University of Minnesota, Minneapolis.
Overall, 1,651 patients (17.7%) had nickel sensitivity and 685 (7.3%) had cobalt sensitivity. The sensitivity rates increased with the number of piercings. The rates of sensitivity among those with zero, one, two, three to four, and five or more piercings were 9.4%, 16%, 22.6%, 25.1%, and 32.4%, respectively, for nickel and 5.3%, 7.6%, 8.2%, 9.5%, and 11.7% for cobalt.
Chromate sensitivity was less common, occurring in only 306 patients (3.26%). Less than 4.3% of patients in all piercing groups had chromate sensitivity, Ms. Loso noted.
"Nickel is the most common allergen for patch-tested patients, and body piercing has been directly correlated with the development of nickel allergy," she said, adding that cobalt content is often associated with nickel content in consumer products, although recent studies suggest that only a small amount of jewelry – mainly earrings – releases cobalt.
In the current study, which involved patients identified using North American Contact Dermatitis Group data from 2007 to 2010, younger patients were affected more often than older patients, females were affected more often than males, and – surprisingly – piercing was associated with allergy in males more often than in females, she reported.
The findings, though limited by the fact that the referral population may not be representative of the general population and by a lack of information regarding age at the time of piercing and the body sites pierced, help characterize metal allergy associated with body piercing, Ms. Loso said.
She noted that nickel allergy has been well studied in Europe – resulting in regulation of the nickel content in consumer goods and a subsequent significant decline in nickel sensitivity among young females there. The same is not true for the United States, where nickel sensitivity remains an important problem.
Ms. Loso reported having no disclosures.