Pediatric Patch Test Screening Series
A summary of the published screening series for patch testing in the pediatric population is provided (Table).
The T.R.U.E. Test (SmartPractice) is approved by the US Food and Drug Administration for use in patients 6 years and older11; however, it may not adequately represent allergen exposures in the pediatric population. Brankov and Jacob14 found that 10 (40%) of their proposed top 25 pediatric allergens were not detected using the T.R.U.E. Test.
In 2014, the North American Pediatric Patch Test Series was proposed as a basic screening panel for children aged 6 to 12 years.12 This series of 20 allergens was developed based on a literature review of pediatric patch test results and case reports as well as a database review. The authors proposed additional allergens to be considered based on patient history.12
More recently, a 2017 American Contact Dermatitis Society physician work group proposed the Pediatric Baseline Patch Test Series. This series of 38 allergens for children aged 6 to 18 years was developed based on expert consensus.8 Studies to determine the efficacy of this series have yet to be conducted, but it may have high sensitivity in detecting relevant allergens in children as demonstrated by a theoretical detection rate of 84%.14
There are 2 recommended patch test series for allergic diaper dermatitis.15 The first series focuses on 23 potential allergens found in wet wipes and topical diaper preparations. The second series contains 10 potential allergens found in diapers. These series contain common topical medications for children including corticosteroids, antimicrobials, and sensitizers specific to diapers such as rubbers and adhesives.15
Similar to adults, it may be difficult to designate one screening panel that can identify all relevant allergens in children; thus, it is always important to obtain a thorough exposure history and customize testing to suspected allergens and/or patient products based on history and clinical relevance.
Unique Pediatric Allergens
Hobbies
Sports gear such as shin guards and splints often contain allergens such as formaldehyde resin, thiuram mix, and dialkyl thioureas.16 Perioral dermatitis may be caused by musical instrument mouthpieces containing nickel.6
Preservatives
Commonly reported causes of ACD in children include methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI) found in wet wipes. A 2016 analysis of diaper wipes showed a low prevalence of MI (6.3%) and MCI (1.6%) in these products, which may reflect the industry’s awareness of these potential allergens and a subsequent change in the preservatives they utilize.17 However, the prevalence of MCI/MI contact allergy may be on the rise due to the popularity of homemade slime, which is made from common household products such as laundry detergent, dishwashing soap, and liquid glue. The Pediatric Baseline Patch Test Series captures most of the potential allergens in these homemade slime recipes and is recommended for use in pediatric patients suspected of having dermatitis secondary to playing with slime.8,18
Toilet Seat Dermatitis
Toilet seat dermatitis presents as a pruritic dermatitis on the posterior upper thighs and buttocks. Although most cases of toilet seat dermatitis are irritant rather than allergic, potential allergens include plastics, fragrances, and components of cleaning products. Thus, physicians should maintain a high index of suspicion for ACD to toilet seats.19
Fragrance and Natural Ingredients
A 2018 study evaluating personal care products marketed specifically for infants and children found that 55% of products (294/533) contained at least 1 common allergen, with fragrance being the most common (48% [255/533]). Other common allergens include betaines (18%), propylene glycol (9%), lanolin (6%), and MCI/MI (3%).20 Caregivers should be advised against the myth that natural products are safer and less allergenic and should be provided with resources such as the Contact Allergen Management Program (CAMP) database (https://www.contactderm.org/resources/acds-camp) for safe alternative personal care products.
Metal Allergens
Nickel, the American Contact Dermatitis Society 2008 Allergen of the Year, is another common allergen that affects children. Nickel allergy, commonly thought to affect the ears due to jewelry and ear piercing, may actually be found in a wide range of daily items such as braces, eyeglasses, keys, zippers, school chairs, electronics, toys, and even food.3,6,21,22 With increased use of electronics in children of all ages, nickel found in mobile phones and other devices may be of particular concern. Caregivers can use a case or cover for metallic-appearing electronics.
Final Interpretation
Pediatric ACD is common. With limited surface area for patch testing in children, we recommend customized panels based on patient history and exposure. It is important for clinicians to recognize the unique causes of ACD in children and develop age-appropriate management plans.