Demodex brevis is a microscopic mite that lives in the hair follicles of humans, particularly on the face. It is part of the Demodex genus, which includes other species that also inhabit human skin. These mites are typically harmless and feed on dead skin cells and oils produced by the skin. While Demodex brevis is a normal part of the skin's ecosystem, an overpopulation can lead to skin issues such as inflammation or irritation. They are most commonly found in individuals with oily skin or certain skin conditions. Regular skin care can help maintain a balanced population of these mites.