Prevention of Atopic Dermatitis: What Are We Missing?

Atopic dermatitis (AD) is a prevalent chronic inflammatory disease that significantly burdens individuals and healthcare systems worldwide. The incidence of AD has risen sharply in both developed and emerging economies, necessitating an understanding of its complex etiological factors, including environmental influences and lifestyle changes. Generally, 2 primary preventive strategies for AD have been implemented so far: (1) the "Inside Out" approach that which involves allergen elimination, probiotic supplementation, fish oil supplementation, and vitamin D supplementation aim to regulate the immune system in pregnancy and early childhood and (2) the "Outside In" approach that focuses on improving skin barrier function through emollient use and environmental changes. Although current evidence suggests the potential benefits from these interventions, randomized controlled trials have revealed inconsistencies in their efficacy. It is imperative not only to explore the minute research gaps in existing studies, but also to develop novel interventional studies that consider individual and regional differences based on the epithelial barrier hypothesis, the biodiversity hypothesis, and the 'old friends' hypothesis evolved from the hygiene hypothesis. Ultimately, reversing the rising trend of AD prevalence will most likely require a multifaceted approach that integrates new scientific evidence and promote comprehensive lifestyle changes.