Early-onset atopic dermatitis phenotypes differ between children, adults
The skin of children with early-onset atopic dermatitis exhibits significantly different phenotypes when compared with the skin of adults with a long-standing history with the disease, according to research published in The Journal of Allergy and Clinical Immunology.
“It is important to recognize the differences in phenotypes between children and adults because different or additional therapeutics may be more suited to children or adults,” Emma Guttman, MD, PhD, vice chair of the department of dermatology at the Icahn School of Medicine at Mount Sinai, told Infectious Diseases in Children. “While the TH2 axis is activated in both children and adults, the TH17 axis is increased primarily in children, similar to psoriasis. Perhaps psoriasis-focused treatments can be applicable to children with atopic dermatitis.”
To describe skin of infants who have atopic dermatitis and compare features with the skin of adults with atopic dermatitis and healthy control subjects, the researchers conducted a microarray, RT-PCR and fluorescence microscopy studies in children aged younger than 5 years. These children experienced the onset of atopic dermatitis before the age of 6 months. Once information was collected, attributes were compared with age-matched control subjects and adults who had established atopic dermatitis.
Guttman and colleagues observed significant differences between the skin of children with early-onset atopic dermatitis and adults who had long-standing atopic dermatitis, with variances found in both lesional and nonlesional tissues. TH2-centered inflammation was demonstrated in the skin of both children and adults; however, pediatric patients also demonstrated significant skewing related to TH17 and TH22. Although adult atopic dermatitis is defined by TH1 upregulation, this was not present in children with dermatitis.
When examining epidermal differentiation and cornification products, pediatric patients with atopic dermatitis had comparatively normal expression, a feature that is downregulated in adults with atopic dermatitis.
Both adults and children with atopic dermatitis demonstrated flaws in the lipid barrier (ELOVL3) and tight junction regulation; however, children exhibited preferential downregulation in some lipid-associated mediators. Furthermore, the lipid barrier genes, such as FA2H and DGAT2, of children with atopic dermatitis were inversely correlated with transepidermal water loss. This measure, according to the researchers, functionally measures the epidermal barrier.
“Children with early moderate to severe disease may need early immunomodulatory interventions to clear their disease and potentially prevent the atopic march,” Guttman said. “Barrier-based approaches are likely not enough to effectively treat moderate to severe disease in early atopic dermatitis in children.” – by Katherine Bortz
Disclosures: The authors report no relevant financial disclosures.