At the crux of all this, as you point out, is the human skin microbiome. That is the collection of bacteria, viruses, fungi and microscopic creatures living on the exterior surface of our bodies.

The skin is an ecosystem, with a microscopic flora and fauna and diverse ecological niches: the desert of the forearm, the cool woods of the scalp and the tropical forest of the armpit ...

Meet Demodex, the face mite, a microscopic arachnid that lives on human skin. The pore is its humble abode and the waxy sebum we secrete is its meal of choice. It's hard to know for sure ...

At the crux of all this, as you point out, is the human skin microbiome. That is the collection of bacteria, viruses, fungi and microscopic creatures living on the exterior surface of our bodies.