Skin microbiota: Friend or foe in pediatric skin health and skin disease

The human integument and gastrointestinal tract host unique microbial ecosystems. Within the last decade, research has focused on understanding the contributions of the microbiota to human health and disease. The majority of skin microbiome studies involve adults. This review focuses on key studies conducted within the pediatric population and provides a framework for future skin microbiome work in this ever-expanding field. This article begins by exploring the skin microbiome at birth and reviews the impact of delivery mode on infant skin colonization. How skin microbial colonization evolves from infancy to adulthood and normal development impacts the abundance of skin commensals such as Streptococcus, Staphylococcus, and Cutibacterium is also highlighted. Finally, several skin microbiome research studies in common pediatric skin conditions are reviewed, including body odor, atopic dermatitis (AD), and acne. The bacteria involved in metabolizing sweat, the impact on body odor, and how this process evolves from childhood to adulthood is outlined. In AD, different bacteria genera that predominate in children and adults and the impact of current AD therapies on skin microbiota are explored. Finally, in acne, the understanding of how Cutibacterium acnes contributes to acne pathogenesis and how acne therapies impact the skin microbial communities is reviewed.