Each area of your body has its own unique microbiome of (mostly good) viruses, fungi, and bacteria. While that might sound a little stomach turning, it’s actually essential, and this microbiome keeps us healthy. The microbiome in your skin, the largest organ in your body, regulates inflammation and serves as a barrier against pathogens, and our skin is first colonised by maternal microorganisms shortly after we are born, and develops and continues throughout our lifetime.
Over time, the composition changes in response to various intrinsic and extrinsic factors. Intrinsic factors include a person’s age, genetics, and overall health. Extrinsic factors include their diet, the climate in which they live and their personal hygiene routine.
The microbial diversity of these colonies also depends on where they are located on the skin and that location’s microenvironment. This is because microorganisms feed on sweat and oil released by skin when it is cooling and lubricating itself. Areas having a higher number of oil glands, such as one’s face, tend to host colonies that feed off on fats (lipids) found in the sebum these glands produce.
Armpits, on the other hand, represent an area that is inherently warm, moist, and dark, resulting in there being a preponderance of microbial colonies that thrive in that type of microenvironment. Then there are skin areas of the skin that are dry and cool, such as forearms or hands, that have fewer colonies due to the relative scarcity of nut.
