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New sources of pediatric contact dermatitis are found in many of the products used by children, parents and even dermatologists. Recognizing these and other emerging allergens could spell fast, effective relief for pediatric patients, as well as prevent misdiagnoses and long-term unnecessary treatments, an expert says.
Chicago - New sources of pediatric contact dermatitis are found in many of the products used by children, parents and even dermatologists. Recognizing these and other emerging allergens could spell fast, effective relief for pediatric patients, as well as prevent misdiagnoses and long-term unnecessary treatments, an expert says.
Nickel and methylisothiazolinone are among today’s most important pediatric allergens, according to Jonathan Silverberg, M.D., Ph.D., M.P.H., assistant professor of dermatology, preventive medicine and medical social sciences at Northwestern University, Chicago.
Nickel has been the most common patch test positive for children and adults for many years. But in recent times, there has been an explosion of nickel use, Dr. Silverberg says.
“Going back about 10 years, we saw a lot of nickel positive patch tests, but they weren’t always relevant,” he says. “Nowadays, we’re seeing a lot more relevant reactions. The metal exposures are coming from technology, including telephones, iPads, tablets, laptop cases.”
Even children who might not be old enough to use phones or computers are at risk. That’s because toys have become more sophisticated, with motorized parts and electronic components. These contain metals, including nickel, Dr. Silverberg says.
And while nickel allergies traditionally occur more often in girls than boys (because girls are more likely to have piercings and get exposure from jewelry), boys seem to be closing the gap.
“Some of the older studies found huge differences in terms of nickel reactions between girls and boys, where girls had tenfold or higher rates of nickel reaction,” Dr. Silverberg says. “We’re seeing a lot more nickel reaction now in boys because of their exposure from some of the other novel sources.”
Allergic reactions from nickel exposure is significant from a public health standpoint because not only has nickel triggered reactions in people who are at risk, but it may be that ongoing nickel exposure in children might predispose them for nickel allergies down the road.
Pediatric skin reactions from cell phones and other devices are not just from the nickel in devices, but also from the many accessories that go along with these technologies, according to Dr. Silverberg.
“We’re seeing (skin reactions from) rubber and dyes that are used on key pads for cells phones. The rubber and plastic cases are a source of allergens. Headphones and ear buds - there’s rubber and plastic in them. The leather casings … all of these can be sources of allergens that can cause allergic contact dermatitis,” he says.
Dr. Silverberg has seen reactions on children’s hands from holding plastic phone casings and reactions in around the ears from headphones and earbuds. These can be either rubber or plastic allergens, he says.
The American Contact Dermatitis Society named methylisothiazolinone Contact Allergen of the Year for 2013 (Castanedo-Tardana MP, Zug KA. Dermatitis. 2013;24(1):2-6. Review).
“This is something that entered the marketplace 10 or 20 years ago and is ubiquitous. There’s basically no skincare category that doesn’t use it in one form or another,” Dr. Silverberg says.
Methylisothiazolinone, a preservative that increases shelf life and prevents bacterial growth, is commonly combined in products with methylchloroisothiazolinone. The mixture, called Kathon CG, is a known to cause allergic contact dermatitis. Researchers reported increases in Kathon CG-associated allergies in the 1980s.
“In unselected eczema patients subjected to routine patch testing, the number with positive reactions to Kathon CG 100 ppm increased from none in 1983 to 0.7 percent in January-August 1985, and to 4.6 percent in September 1985 to March 1986,” according to the study (Hannuksela M. Contact Dermatitis. 1986;15(4):211-214).
In Europe, the documented frequency of allergy to Kathon CG is about 1.5 percent, according to the study by Castanedo-Tardana and Zug.
“The frequency of allergy to this preservative in the United States is unknown. If you are not testing for allergy to this preservative, you may be overlooking the importance of a very relevant preservative allergen that, to date, has managed to stay under the radar in the United States,” Dr. Silverberg says.
While it’s useful as a preservative, methylisothiazolinone alone can be irritating and allergenic, he says. As a result, Dr. Silverberg is seeing cases of allergic contact dermatitis where they don’t usually occur.
“We’re seeing a lot of perianal reactions to baby wipes. In young kids, we’re seeing those reactions particularly in children known to have inflammatory bowel syndrome or any other causes of diarrhea,” Dr. Silverberg says. “We’re seeing facial reactions and hand eczema due to a number of moisturizing creams and lotions and kids being cleaned with wipes by their parents. We’re seeing generalized reactions from shampoos and conditioners. It’s just everywhere.”
Methylisothiazolinone is an ingredient that dermatologists might not think about. But, the fact is, it’s even in some of the prescription topical medications they prescribe, Dr. Silverberg says. These include crotamiton (Eurax, Ranbaxy), halobetasol propionate 0.05 percent cream (Ultravate, Ranbaxy) and some triamcinolone cream preparations, which are mainstays of treating inflammatory skin disease.
Methylisothiazolinone is also in over-the-counter products dermatologists might recommend to pediatric patients, such as Dove Soap, Dove Body Wash and Head & Shoulders shampoo.
These products might not be irritating, initially. However, one of the major risk factors for developing contact dermatitis is frequency of use.
“If you use the same product and it has allergenic potential, you can develop an allergy over time,” Dr. Silverberg says. “Or, if patients have an allergy to methylisothiazolinone, providers need to be aware that they can’t be using these creams and topical prescriptions or make over-the-counter recommendations where they might be directly exposing patients to these allergens.”
Often patients who are using topical agents and are allergic or develop an allergy to methylisothiazolinone will experience some improvement initially because the steroid suppresses inflammation. But, almost immediately after, they get a worsening because they’ve been exposed to an allergen.
“When you see that kind of rebound, you really need to think about some kind of allergen,” he says.
Dermatologists can check product inserts for methylisothiazolinone, and should refer patients for patch testing if they suspect a skin allergy.
“If you’re really suspicious, don’t hesitate. It’s better to refer for patch testing and be certain about it. Otherwise, some of these patients will go on for years or decades with a chronic disease, where it’s never well controlled. It might be as simple as changing around some products and avoiding some allergens and everything gets better or goes away,” Dr. Silverberg says.
And while he admits finding products without the preservative might be a challenge, Dr. Silverberg says it’s worth it for patients.
Dermatologists should at least entertain the possibility of a methylisothiazolinone-related or another contact dermatitis every time they see a child with an eczema-like rash.
“It can show up commonly in … those localized eczema reactions. So, really tough hand eczema or eczema that just keeps coming back that’s localized to a particular body,” Dr. Silverberg says. “Nummular or coin-shaped eczema - a number of studies have shown that to be highly related to contact allergies. Even just the garden variety of atopic dermatitis can be confounded by contact dermatitis.”
Some dermatologists still believe in the conventional dogma that atopic dermatitis somehow cancels out an increased risk of allergens. But recent research tells a different story.
“This year, at the American Contact Dermatitis Society meeting, there were (many) studies that presented higher rates of contact dermatitis in atopic dermatitis,” he says. “So, even for those garden variety eczema cases, if you’re thinking about putting them on prednisone, systemic agents or phototherapy, you’re really obligated to patch test them first, to make sure that it’s not some reversible thing.”
In one of those studies, researchers reported evidence from the U.S. and Europe that suggests people with atopic dermatitis have similar if not higher rates of positive patch test results to common contact allergens, including metals and fragrance, than people without atopic dermatitis (Aquino M, Fonacier L. J Allergy Clin Immunol Pract. 2014;2(4):382-387).