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SUMMARY POINTS
What’s Important?
Diversity in the bacterial microbiome is the healthiest state.
It is too soon to recommend probiotic skincare products.
Diet and environment play a major role in the microbiome.
What’s New?
The skin and gut microbiome play a role in skin inflammation.
The microbiome allows communication with the gut, brain, and skin.
What’s Coming?
Understanding the effects of skin and gut microbiomes on skin disease.
Healthier ways to manipulate the microbiome to treat skin issues.
Identifying which combinations of bacteria have the best outcomes in skin disease.
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In this era of personalized or precision medicine, we have come to learn about the great deal of recent research focusing on the gut microbiome and its role in individual health. Human skin, too, hosts a copious and disparate array of bacteria, fungi, viruses, and arthropods, with as many as a billion microbes inhabiting a single square centimeter of skin.1,2 And these microbes, too, play an important role in skin health that research is now uncovering. Human skin, the largest organ of the body, serves not only as an ecosystem but also as a protective barrier against pathogenic microorganisms and other exogenous material, and we are elucidating much more about the microbiome of the skin and its balancing act between beneficial, neutral, and harmful flora mediated by the innate and adaptive immune systems.3
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As Dréno et al. remind us, Antoni van Leuwenhoek made the first discovery that the skin hosts a wide array of microscopic creatures in 1683.3 Modern techniques have verified that, indeed, the human skin is colonized by an abundance of diverse microscopic communities. These microbes play an important role in skin health and disease. It should be noted that less is known about viral species than any other genera of the cutaneous microbiome.3 The body of knowledge on microbes is most advanced on bacteria, which also are predominantly implicated in some of the skin disorders discussed here.
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The skin, like the gut, plays a significant role in human health as an interface organ. As noted by O’Neill et al., the skin also expresses several co-morbidities with gut disorders.4 Bacteria, more than other microbes, also constitute a preponderance of the gut microbiome, and the skin-gut nexus warrants exploration as these critical interface organs can impact one another in health and disease.
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Dysbiosis is said to have occurred when a healthy equilibrium is disrupted by a microbial imbalance internally or externally. Infections, wounds, and microbial colonization are all regulated by the cutaneous immune system; dysregulation of this system manifests in various skin conditions.5 The etiologies of various skin disorders, including acne, atopic dermatitis (AD), seborrheic dermatitis, hidradenitis suppurativa, and chronic wounds, have been ascribed, at least in part, to microbial sources.5,6 Research into the dynamic role of the skin microbiome in cutaneous health and disease ...