The gut is not the only part of the human body that hosts an important microbiome. The surface of the skin is home to a sprawling and complex microbial ecosystem, which interacts with the immune system and influences dermatological health. The gut is not the only part of the human body that hosts an important microbiome. The surface of the skin is home to a sprawling and complex microbial ecosystem, which interacts with the immune system and influences dermatological health.