More frequent testing for nickel allergies in children might help keep the allergies from developing, according to a report in Pediatric Allergy and Immunology.
The study, at the University of Southern Denmark, found that teenagers tested for nickel allergy multiple times before age 3 had significantly lower rates of allergy to the metal at age 14 than teens who weren’t tested as children. The two groups of teens were tested with identical test kits containing minute amounts of nickel sulfate that was absorbed through the skin. The study involved some 1,750 participants.
The researchers previously reported that among the frequently tested children, 62% had positive tests for nickel allergy before age 3 but tested negative at ages 3 and 6. This follow-up study suggests that exposure to nickel during repeated patch testing may have increased their physiological tolerance or sensitivity to nickel.
The prevalence of food allergy, eczema and ear piercings was similar in both groups. Girls had more positive tests than boys.
The North American Contact Dermatitis Group estimates that 11 million U.S. children are allergic to nickel. The metal is found in jewelry, zippers, coins, cellphones and other products and can cause severe skin reactions.