Topical Corticosteroids Normalize both Skin and Systemic Inflammatory Markers in Infant Atopic Dermatitis.

Background Atopic dermatitis (AD) is the most common inflammatory skin disease. It is highly heterogeneous in clinical presentation, treatment response, disease trajectory and associated atopic comorbidities. Immune biomarkers are dysregulated in skin and peripheral blood. Aims We used non-invasive skin and peripheral biomarkers to observe the effects of real-world topical corticosteroid treatment (TCS) in infants with AD, by measuring skin and blood biomarkers before and after therapy. Methods 74 treatment-naive infants with AD underwent six-weeks TCS treatment. Stratum corneum (SC) and plasma blood biomarkers as well as SC natural moisturising factor (NMF) were measured before and after TCS therapy. Immune markers included innate, Type 1 and 2 immunity, angiogenesis, and vascular factors. AD severity was assessed by SCORAD and skin barrier function by TEWL. 20 healthy infants were recruited as controls. Results TCS therapy predictably led to improvement in disease severity. Levels of immune markers in the skin and in the peripheral blood showed significant change from baseline, though most did not reach healthy control levels. The most prominent change from baseline in SC was in markers of innate activation: IL-18, CXCL8, IL-1α and Th2 chemokines CCL17 and CCL22. In blood, the largest changes were in Type 2 skewed biomarkers: CCL17, IL-13, CCL22, IL-5, and CCL26. TEWL decreased after therapy; no significant changes from baseline were found for NMF. Conclusions Profound impact of topical therapy on systemic biomarkers suggests that the skin compartment generates a major component of dysregulated systemic cytokines in infant AD. There may be long term beneficial effects of correcting systemic immune dysregulation through topical therapy.