Pediatric atopic dermatitis (AD) in infants looks a lot different than adult AD, suggesting the need for alternative, and possibly more aggressive, treatment strategies in children.

The study, led by researchers at the Icahn School of Medicine at Mount Sinai in New York City and Northwestern University’s Feinberg School of Medicine in Chicago, appears in the Journal of Allergy and Clinical Immunology.

Emma Guttman-Yassky, MD, PhD, Professor of Dermatology and Immunology, and Vice Chair of the Department of Dermatology at the Icahn School of Medicine, and Amy S. Paller, MD, Walter J. Hamlin Professor and Chair of the Department of Dermatology at Northwestern, investigated lesional and non-lesional skin biopsies from 19 AD infants under the age of five, and compared them to age-matched pediatric controls, in addition to adult AD biopsies. 

They found that the normal-appearing skin of young children with early eczema is already highly abnormal with significant immune activation, simulating that of lesional skin of adults with many years of active disease.

The study also highlighted some important differences between the adult and pediatric phenotypes.  Pediatric AD is associated with increased lymphocyte activation, including Th2 lymphocyte cells, which is also similar to adults with AD, but unlike the adult disease, the pediatric eczema profile has robust and significant increases of Th17 T lymphocyte cells, which are characteristically increased in psoriasis, a disease that is now being successfully targeted in using anti IL-17 and IL-23-targeting strategies. 

“It is clear that multiple cytokines are elevated in pediatric AD, and that  only targeting TH2-driven inflammatory processes may not be enough, “Dr. Guttman-Yassky tells Dermwire. “We need to think about targeting other axes including those that are elevated in psoriasis.”

The study showed no abnormalities in pediatric eczema skin in filaggrin, challenging the classically held idea of filaggrin deficiency as an instigator of the atopic march. Additionally, the researchers found that early eczema skin does not show the deficiency in skin-produced infection-fighting proteins that has been described in adult eczema skin.

This suggests a role for prevention in high-risk individuals. “We know that by applying emollients, we can reduce risk of AD, but once you have disease, you must treat it,” she says. “If we treat AD early and very aggressively, we may be also prevent the atopic march. It’s a really exciting time in AD,” she says.