Dr. Jonathan I. Silverberg
“Maybe not,” Jonathan I. Silverberg, MD, PhD, MPH, said during the Revolutionizing Atopic Dermatitis symposium.
Dr. Silverberg, director of clinical research in the division of dermatology at George Washington University, Washington, based his comments largely on a review that he and his colleagues carried out to understand how features of atopic dermatitis (AD) vary by region globally as well as by age. They identified 101 studies with sufficient data for meta-analysis and stratified the results by pediatric and adult age groups.
Several signs and symptoms occurred with similar frequency among pediatric and adult patients, including pruritus, xerosis, flexural involvement, extensor involvement, early onset of disease, comorbid atopy, head and neck involvement, and ophthalmic comorbidities. However, adults were found to have more signs of chronic disease, more hand eczema, different patterns of hand eczema, and a stronger relationship of disease activity with emotional factors. Meanwhile, children were found to have more exudative or weeping lesions, more perifollicular eczema, and more pityriasis alba.
Dr. Silverberg showed photos of three adults with varied presentations of extensor involvement, including one “who had a lot of lichenification and thickening of the skin, but over knees where you might think about psoriasis,” he said. “All three of these patients were of Southeast Asian descent. That happens to be a region where this feature was reported much more commonly. It may even tie to some underlying immunopathophysiologic differences of the disease across different patient populations.”
AD signs that occur more commonly in adults than children include lichenification (100% vs. 48%), urticaria (32% vs. 20%), popular lichenoid lesions (46% vs. 8%), Hertoghe’s sign (25% vs. 2%), erythroderma (29% vs. 1%), and nodular prurigo (18% vs. 4%).
Hand eczema features also differ between adults and children, including hand or foot dermatitis (44% vs. 25%), dyshidrosis/pompholyx (21% vs. 3%), knuckle dermatitis (25% vs. 8%), nail involvement (15% vs. 8%), and fissured heels. However, ventral wrist dermatitis was found to be more than twice as common in children, compared with adults (34% vs. 15%).
Other signs of AD were more common in children, compared with adults, including exudative eczema (61% vs. 42%), pityriasis alba (28% vs. 18%), Dennie-Morgan infraorbital folds (47% vs. 36%), seborrheic dermatitis–like lesions (40% vs. 18%), and perifollicular accentuation (37% vs. 21%). “This is such an important sign to wrap your head around and get comfortable assessing,” he said. “I have seen patients who are erythrodermic with follicular eczema who were told that they were crazy and had psychogenic itch, and they should go to a shrink.”
AD triggers can differ between adults and children as well, including course influenced by emotions/environmental factors (72% vs. 32%), worsening itch worse (65% vs. 49%), course influenced by environment (62% vs. 37%), and course influenced by emotions (70% vs. 15%).
According to Dr. Silverberg, emerging research suggests that there may be differences in the immune pathways activated in pediatric versus adult AD. Specifically, more Th17 and interferon-gamma in AD lesions have been observed in children, compared with adults, and more Th22 and Th17 in nonlesional AD have been seen in children, compared with adults. “This leads to a question: Will children respond differently than adults to treatment?” Dr. Silverberg said. “We see that omalizumab doesn’t seem to help much in adults, yet a recent study suggested that it might work reasonably well for children. Dupilumab has different dosing requirements and potentially different responses between the pediatric and adult populations.”
Age differences in AD may also be related to differences in the skin microbiome. In 2016, researchers led by Richard L. Gallo, MD, PhD, professor of dermatology, University of California, San Diego, compared the skin microbiome between adults and children with AD by swabbing the volar forearm and performing 16S rRNA gene sequencing. The study included 59 young children, 13 teenagers, and 56 adults with AD as well as 68 age-matched non-atopic healthy controls. The researchers found a greater abundance of Streptococcus, Granulicatella, Gemella, Rothia, and Haemophilus in young children, compared with adults, while Propionibacterium, Corynebacterium, Staphylococcus, Lactobacillus, Finegoldia, and Anaerococcus were more abundant in adults, compared with children.
Dr. Silverberg reported that he is a consultant to and/or an advisory board member for several pharmaceutical companies. He is also a speaker for Regeneron and Sanofi and has received a grant from Galderma.