Hair follicles, the root ends of the hairs, are embedded in your skin and surrounded by clusters of sebaceous glands, special glands that produce sebum.
These microbes, which include bacteria and fungi, thrive in the sebum, an oily substance that's secreted onto the skin's surface by sebaceous glands nestled inside the dermis.
Think for example of a dermoid cyst, with its mixture of tissues like hair and sebaceous fluid: that’s not something the peritoneal cavity is meant to handle!