Studies of the skin microbiome that exist on and within the human body is a fairly recent field, though holds potential to revolutionize the way we think about our health and immune systems. The skin microbiome is defined as the microorganisms (or microbiota), such as bacteria, fungi, and viruses, which occupy the skin's environment. We most often hear about the microbiome of our gut, though they exist across the skin and other organs as well. External microbiomes are categorized into four habitats:

• Oily (ex. Forehead)
• Moist (ex. Inner elbow)
• Dry (ex. Forearm)
• Podiatric (exclusive to the foot)

Humans and their microbiomes are symbiotic, meaning there are mutual benefits for everyone involved! However, the relationship is delicately balanced. When disrupted, unwanted skin conditions may begin to appear. 

Propionibacterium acnesis the most abundant microorganism across the skin of healthy adults. When it grows in excess or settles deep within follicles and pores, it is responsible for acne vulgaris.Staphylococcus aureus overpopulation is associated with psoriasis and atopic dermatitis, the most common form of eczema. Even health threats as serious as staph infections, related to the mutation or overgrowth ofStaphylococcus epidermis come from an aggravated microbiome. These ailments are all related to dysbiosis, exemplifying that maintaining a healthy skin microbiome is the best protection against a range of unwanted skin conditions.

Your exact skin microbiome is as distinctive as your fingerprint, and it is established within the first few weeks of your life. While there are recognized healthy population ranges for the microbiota, what’s best for your skin is personal and unique. For this reason, it is very difficult to treat with pro- and prebiotic. The best methods for maintaining your microbiome’s balance are simple lifestyle actions:

• Stick to towels, pillowcases and clothing made of natural materials - they are less likely to harbor harmful bacteria and fungi
• Wear breathable, loose clothing (especially when working out) – most microorganisms thrive in dark, oxygen starved conditions, and are therefore more likely to overpopulate when trapped tightly against your skin
• Avoid cosmetics and skin care products with harsh preservatives and synthetic ingredients – these are known to alter your skin’s pH, disturbing the microorganisms’ delicate living conditions
• Avoid excessive sterilization – while you can never eliminate your microbiome, constant and aggressive washing may deplete some species and allow others to overgrow in their place
• Don’t share cosmetics, or use them past their expiration date – the older or more widely shared a product is, the more likely it is to have contaminating microorganisms that can colonize and alter your microbiome

Remember that your skin microbiome is an evolutionary advantage to help, not hurt, your body. The bacteria, viruses, and fungi which inhabit your skin are not products of poor hygiene. It is a self-balancing system that can thrive so long as you take proper care of its external conditions. Support it with daily choices, and it will continue to support you in return!

Sources:

1. Byrd, A. L., Belkaid, Y., & Segre, J. A. (2018). The human skin microbiome. Nature Reviews Microbiology, 16(3), 143.
2. Grice, E. A., & Segre, J. A. (2011). The skin microbiome. Nature reviews microbiology, 9(4), 244- 253.
3. Krutmann, J. (2009). Pre-and probiotics for human skin. Journal of dermatological science, 54(1), 1-5.
4. Maguire, M., & Maguire, G. (2017). The role of microbiota, and probiotics and prebiotics in skin health. Archives of Dermatological Research, 309(6), 411-421.
5. Staudinger, T., Pipal, A., & Redl, B. (2011). Molecular analysis of the prevalent microbiota of human male and female forehead skin compared to forearm skin and the influence of make‐up. Journal of applied microbiology, 110(6), 1381-1389.