AT WCPD 2017
CHICAGO (FRONTLINE MEDICAL NEWS) – If severe eczema persists in a pediatric patient despite your best treatment efforts, think allergic contact dermatitis.
“Or, if your eczema patients tell you that they have a cream that’s making things worse, you should think about a contact allergen,” Catalina Matiz, MD , said at the World Congress of Pediatric Dermatology.
Allergic contact dermatitis (ACD) is a type IV delayed-type hypersensitivity reaction to haptens that come into contact with the skin. Poison ivy is a common plant-based culprit, while nickel is the most common metal allergen in adults and children. “The skin barrier also plays a role,” said Dr. Matiz of the department of dermatology at Rady Children’s Hospital–San Diego, and the University of California, San Diego. “Compared with adults, children have a thinner stratum corneum, and some haptens can penetrate the skin. Some studies suggest that patients with atopic dermatitis may have increased rates of allergic sensitization, and filaggrin mutations have been found in patients with atopic dermatitis and in patients with ACD to nickel. Filaggrin helps to aggregate the cytoskeletal proteins that form the cornified cell envelope. Without filaggrin, the skin barrier is defective.”
Atypical locations for atopic dermatitis (AD) that should make you think of allergic contact dermatitis include the eyelids, perioral area, scalp, neck, extensor surfaces, hands and feet, and genitalia. First-line treatment involves an adequate potency of corticosteroids. “Most of the time, you need mid- to high-strength corticosteroids for body lesions,” Dr. Matiz said. “If you suspect poison ivy or severe contact reactions, you may need to treat with systemic corticosteroids with a slow taper of 3-4 weeks. It’s important to improve the skin barriers with the use of moisturizers and you want to limit the use of irritant products as well. These include fragrances, formaldehyde, and cocamidopropyl betaine. Avoidance of the suspected culprit is very important.”
The top 10 pediatric allergens found in personal hygiene products across five studies in the medical literature include neomycin, balsam of Peru, fragrance mix, benzalkonium chloride, lanolin, cocamidopropyl betaine, formaldehyde, methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), propylene glycol, and corticosteroids. Dr. Matiz makes it practice to patch test as a last resort. “I always try to get a history, try to improve their symptoms, and have them start avoidance first, following the preemptive avoidance list,” she said ( Expert Rev Clin Immunol. 2016;12[5]:551-61 ).
The T.R.U.E. test includes 35 allergens. “The T.R.U.E test is a good tool, which can capture up to 70% of relevant reactions in children with the inconvenience that some of the allergens in the test are not that relevant in children, and it’s not yet [Food and Drug Administration] approved to use in children,” she noted. The comprehensive chamber test allows you to select from unlimited number of allergens, “but that’s difficult. You have to have specialized staff to help you make the cells.”
A list of the minimum 20 allergens you should test for in children and the recommended supplemental allergens depending on history and locations of their dermatitis can be found in the following article: Curr Allergy Asthma Rep 2014;14[6]:444 . “I always tell patients when they come for consultations to bring in everything they’re using: their shampoos, creams, and medications, because we want to see what they’re exposed to, so we can select the right allergens and also test their own products,” Dr. Matiz said. She recommends avoiding testing for strong sensitizers such as paraphenylenediamine, in children younger than 12 years of age who don’t have a history of exposure.
Testing tips for children younger than age 5 include decreasing concentrations to half for nickel, formaldehyde, and rubber accelerators. “Don’t test for paraphenylenediamine unless there is high suspicion,” she said. “Consider removing patches by 24 hours in the very young.”
The best antidote to contact dermatitis is avoidance of the known trigger. “You want to spend a lot of time with patients and parents on this,” she advised. “Give a list of safe products to use from the American Contact Dermatitis Society’s Contact Allergen Management Program [ www.contactderm.org ], and provide handouts about the location and history of positive allergens [ www.truetest.com ].” And, she added, “make a plan of treatment and follow-up in 6 weeks.”
Dr. Matiz disclosed that she is a subinvestigator in the Clinical Evaluation of T.R.U.E Test Panel 3.3 in Children and Adolescents study.
