Allergic contact sensitivity to nickel is statistically associated with body piercing and this relationship appears to be exposure dependent and stronger in males, according to a North American study published in Dermatitis (Oct. 2014; 25(5):255–264).
“The goal of this study was to look at the association between body piercing and positive reactions to nickel, cobalt, and chromium in patients with dermatitis who have been patch-tested in the United States and Canada, ” said lead author Dr. Erin Warshaw, dermatologist and professor at the University of Minnesota, Minneapolis.
This retrospective analysis involved 9,334 dermatitis patients who were tested by the North American Contact Dermatitis Group (NACDG) between Jan. 1, 2007 and
Dec. 31, 2010, Dr. Warshaw told The Chronicle of Skin & Allergy.
Each of the participants were patch tested using the NACDG standard series of 65 to 70 allergens, which included three metals: nickel (nickel sulfate, 2.5% petrolatum), cobalt (cobalt chloride, 1.0% petrolatum), and chromium (potassium dichromate, 0.25% petrolatum).
Findings revealed that nickel sensitivity was statistically associated with at least one piercing (risk ratio [RR], 2.52; 95% confidence interval [CI], 2.26–2.81; p<0.0001) and nickel sensitivity rates increased with the number of piercings (16% for one piercing to 32% for ≥5 piercings).
In addition, the authors reported that the prevalence of nickel sensitivity was higher in females
(23.2%) than in males (7.1%), but the association with piercing was stronger in males
(rr, 2.38; 95% CI , 1.72–3. 30; p<0.0001) than in females (RR, 1.30; CI, 1.13–1.49; p=0.0002).
Crude analysis indicated that cobalt sensitivity was statistically associated with piercing (RR, 1.63; 95% CI, 1.40–1.91; p<0.0001); however, stratified analysis showed that this relationship was confounded b ynickel. Subsequently, the authors also indicated that after adjusting for nickel sensitivity, the adjusted risk ratio for piercing and cobalt was 0.78, which the investigators considered not significant. On the other hand, chromium sensitivity was negatively associated with piercing (RR, 0.60; 95% CI, 0.48–0.75; p<0.0001).
Nickel sensitivity increased with number of piercings, study found
“I think one of the most important findings from our investigators was that nickel sensitivity is associated with at least one piercing, ” Dr. Warshaw said.
“Interestingly, data also suggested that nickel sensitivity rates were higher in participants who had a greater number of piercings; therefore, a dose response relationship was discovered.”
Dr. Warshaw added that the researchers found that the association between nickel allergy and piercing was stronger in males than in females.
“We hypothesize that there was a stronger association with piercing and nickel sensitivity in men because their frequency of jewelry use is likely much less than women, therefore,
males’ risk for being sensitized to nickel from a source other than piercing is
lower,” she suggested.
“In places of the world such as Nigeria, where men tend to wear costume jewelry at similar rates to women, there appears to be no difference in nickel allergy prevalence between both genders.”
Call for regs limiting nickel content
“Our findings suggest a nickel allergy piercing association and in response to that I hope the U.S. government will step in and consider regulations on the allowable amount of
nickel release from consumer products, similar to the regulations that are now in place in europe,” she said. The American Contact Dermatitis Society has been worki ng on a nickel
Directive initiative with this goal.
“European studies have clearly documented that limiting nickel exposure is successful in decreasing nickel allergy in young females.”
Originally published in the June 2015 issue of The Chronicle of Skin & Allergy