Updates in Pediatric Allergic Contact Dermatitis: What’s Hot and What’s Not

Dr. JiaDe Yu presented information about pediatric allergic contact dermatitis (ACD). ACD is a skin rash caused by direct contact with an allergen. 

JiaDe Yu, MD, MS, chair and associate professor of dermatology, Virginia Commonwealth University School of Medicine

First, Yu discussed the prevalence of pediatric ACD. An estimated one-third of children will develop ACD; it may be overlooked because atopic dermatitis (AD) may have a similar appearance and is highly prevalent in children. ACD occurs in children as young as six months old. ACD prevalence decreases as children grow, but the reasons are unclear. Pediatric patch tests have higher false positive rates compared with patch tests in adults; clinicians need to be highly competent at patch testing to be effective. It is unknown whether children can grow out of ACD. Evidence suggests that certain metal allergies, including nickel, cobalt, chromium, and aluminum improve with time. The most common causes of pediatric ACD include hydroperoxides of linalool and limonene (fragrance), nickel, cobalt, and methylchloroisothiazolinone (preservative).

Second, Yu described patch testing for pediatric ACD. He emphasized that not every child with AD needs to be patch tested for ACD. Eczema that involves the elbow crease, popliteal, wrist, or back of the neck is unlikely to be ACD. Dermatologists should consider patch testing in certain cases including:

• Patients with isolated eczema of the eyelid, upper lip, or feet
• Patients with eczema that does not improve with topical treatments, as the patient may develop ACD to the treatment or treatment vehicle
• Older pediatric patients with new-onset eczema

Dermatologists should conduct patch testing for as many allergens as possible. Adults are routinely tested for >100 allergens; children have less space on their backs for testing. Patch testing options include thin-layer rapid use epicutaneous (T.R.U.E) test (35 allergens), pediatric baseline series (PBS) (40 allergens), American Contact Dermatitis Society core series (90 allergens), North American Contact Dermatitis Group (NACDG) series (80 allergens), and site-dependent series. In his clinic, Yu starts with the NACDG for children older than six years and the PBS for children younger than six years. In smaller children, Yu customizes the patch testing based on the family’s chief complaints.  

Yu encouraged dermatologists to patch test children with suspected ACD because it improves dermatologic outcomes. Results from one study of 51 children showed that 14 (28%) completely improved after patch testing and 28 (55%) partially improved. Most of the children who had partial improvement had a history of atopy. Yu counsels families that curing ACD does not cure AD.

Third, Yu shared two patient cases demonstrating increasingly common causes of pediatric ACD. 

Case 1

A 16-year-old male presented with new-onset eyelid dermatitis. The patient had used topical triamcinolone and tacrolimus, but flares continued. Patch testing was positive for cobalt. The patient’s mother shared that her son frequently consumed Monster energy drinks, which contain high levels (490% daily value) of vitamin B12. 

Vitamin B12, also known as cobalamin, contains cobalt molecules that can induce ACD. Yu sees vitamin B12-related ACD in adults after bariatric weight loss surgery because they are heavily supplemented with vitamin B12 to prevent anemia. This patient’s ACD improved with reduced vitamin B12 intake. Yu now routinely asks patients about vitamin B12 as part of ACD screening. 

Case 2 

A 15-year-old male with type 1 diabetes presented with a rash 10 days after starting the Dexcom G7 continuous glucose monitor (CGM). The rash was located at the CGM site; Yu suspected a diagnosis of ACD. 

More than one-third of patients using CGMs report dermatitis that appears weeks, months, or years later. The most common causes of CGM-related ACD are acrylates, colophonium, and epoxy resin in the CGM adhesive. The contents of CGM adhesives are proprietary information; Yu looked in the literature for studies that had analyzed them. Results from one study identified isobornyl acrylate and colophonium in the Dexcom G7.

Patch testing for this patient was positive for colophonium, identifying the cause of the patient’s rash. Finding a different CGM that does not cause ACD is a process of trial and error. Yu is conducting an ongoing study to determine the components of over-the-counter CGMs.

Finally, Yu described gaps in knowledge about ACD and areas for future research. Case reports and case series are needed to understand the components of adhesives and CGMs that cause ACD. Longitudinal data will improve understanding of the changing prevalence of pediatric ACD with age and exposure.

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