The skin is the human body’s largest organ. It’s colonized by a diverse milieu of microorganisms, most of which are harmless or even beneficial to their host. All of the microbes that live on the skin collectively make up the skin microbiome, sometimes referred to as microflora or microbiota.
The skin is also an interface between us and our environment and, as such, colonized by a diverse collection of microorganisms including bacteria, fungi and viruses. Symbiotic microorganisms occupy a wide range of skin niches and protect against invasion by more pathogenic or harmful organisms.
The microbiome doesn’t just exist on the surface of the skin: it reaches as far as the subcutaneous fat layer, signaling an inherent connection and even communication with the immune system. While the majority of the immune system is housed in the gut, it’s highly mobile and interacts with the bacteria on skin.
Optimal health for the skin requires a delicate balance between the communities of microbes living in and on the skin. Like the good bacteria found in other microbiomes of your body, the flora found on your skin are designed to protect you from unwanted irritants and invaders that can cause breakouts, fine lines, and other issues.