We’re all familiar with the balance of good and bad bacteria and other microorganisms that make up our unique microbiome, particularly in areas like our gut. Did you know that our skin also has its very own microbiome of good and bad microorganisms?
The skin is the largest organ of the human body and its primary role is to serve as a physical barrier that protects our blood and organs from potential attack by foreign organisms or toxic substances. It’s an interface with the outside environment and, as such, is colonised by a diverse collection of bacteria (as well as some viruses and fungi, too).
Each area of the skin has its own ‘family’ of bacteria, differing from our forearms to our armpits and in between our toes. Most of this bacteria is harmless or even beneficial for our health. The colonisation of bacteria and other microorganisms on our skin is driven by the skin’s surface that is highly variable due to many factors, including hygiene practices, the environment and genetics. In normal adult skin, it is estimated that there are up to 2 million bacteria per square centimetre!
What kinds of microorganisms make up the skin microbiome?
As mentioned above, different areas of the skin are inhabited by different types of bacteria/microorganisms. Drier areas like the shins and forearms are colonised by different bacteria compared to moister areas like the armpits and oilier areas like the face and back.
Most of the bacteria on our skin live in the superficial layers and in the upper parts of the hair follicles. Some bacteria however reside in the deeper areas of the hair follicles and are beyond the reach of ordinary cleaning procedures. These deeper microorganisms act as a reservoir for recolonization after the surface microorganisms have been removed.
The following are the most abundant types of bacteria that live in the superficial layers of the skin and upper parts of the hair follicles:
Staphylococcus epidermidis is a major inhabitant of the skin and in some areas, it makes up more than 90% of the total microorganisms. It naturally possesses antibacterial properties, keeping a balance between the good and bad microorganisms on the skin, however it is the type of bacteria most responsible to cause infections after medical procedures that involve piercing or cutting the skin (this is why doctors and nurses clean our skin with alcohol before blood tests!).
Staphylococcus aureus comprises up to 40% of our skin’s total microbiome. It is typically found in and around our nostrils and also the vulvar skin. It is the most common type of bacteria found on the skin of people who suffer from atopic dermatitis. Its role is to enhance the immune response to ward off other pathogenic bacteria.
The Corynebacterium bacteria are most commonly found in areas of the skin that are rich in sebaceous (oil) glands, particularly the face, scalp, back and upper arms. This family of bacteria can contribute to acne and infections of the hair follicles. Children under 10 years of age or who haven’t yet reached puberty are rarely colonised with Corynebacterium as the sebaceous glands aren’t typically active as of yet. They’re not all bad though – some of the Corynebacterium are thought to have antioxidant benefits, protecting our skin cells from oxidative damage.
The Micrococcus species of bacteria are tiny, spherical-shaped bacteria that are typically not pathogenic. They are important at keeping the balance amongst all the other bacteria and microorganisms of the skin.
What factors can impact our skin microbiome?
Generally speaking, most people actually have similar skin microbiomes with slight variations due to age, the environment and certain medical conditions. At birth, our skin is initially colonised by bacteria from the birth canal, however babies born via caesarean section are sterile and colonised later on through human touch and from the environment.
As life goes on, each of the following play a role on our skin microbiome:
- Environmental temperature and moisture
- Sun exposure (sun burn damages the balance of good bacteria on our skin)
- The health of our immune system
- Genetics
- Some medications, particularly antibiotics
- Hygiene practices and products
- Having pets in the home
How can I improve my skin microbiome?
The majority of the bacteria and microorganisms on our skin are there to protect us, so it’s important to remember this when showering! Avoid using harsh soaps/body wash that void the skin of these beneficial microorganisms, as well as harsh loofas or body exfoliators. Don’t forget about water temperature either - water that’s too hot can disrupt the balance of the skin microbiome.
As mentioned earlier, sun burn not only damages our skin cells but also the bacteria and microorganisms that live there. Be sun smart by avoiding prolonged exposure to the sun and remember to wear sunscreen and/or cover your skin with appropriate clothing, hats and sunglasses when needed.
Keep your skincare simple – every product we apply to our skin has the ability to affect our microbiome. Opt for skincare products that are free from harmful preservatives and are rich in natural ingredients, like our very own Vitamin E Cream and our Ageless Skin Care Range.
Probiotics can be helpful, too! Just as we take probiotics for gut health, research is emerging to show the role of probiotic supplements on the health of the skin microbiome. Probiotics are naturally found in fermented foods like yoghurt, sauerkraut and kefir, or you can buy them in supplement form such as our Probiotic 32 Billion and Probiotic SB.
REFERENCES
- Byrd, A.L., Belkaid, Y., Segre, J.A. (2018), the human skin microbiome, Nature Reviews Microbiology 16(3): 143-155
- Grice, E.A., Segre, J.A. (2011), The skin microbiome, Nature Reviews Microbiology 9(4): 244-253
- Davis, C.P. (1996), Medical Microbiology, 4th Edition, Chapter: Normal Flora
- Lee, N. (2014), Microorganisms found on the skin, DermNet NZ, cited on 24/2/2020, accessed <https://dermnetnz.org/topics/microorganisms-found-on-the-skin/>
- Otto, M. (2009), Staphylococcus epidermidis – the “accidental” pathogen, Nature Reviews Microbiology 7(8): 555-567
- Prescott, S.L. et al. (2017), The skin microbiome: impact of modern environments on skin ecology, barrier integrity and systemic immune programming, World Allergy Organisation Journal, 10(1): 29
- Tannock, G.W. (1999), Medical Importance of the Normal Microflora, Chapter: The human skin microflora and disease, pp. 24-46, Springer Science
- Wong, V.W. et al. 92013), From Germ Theory to Germ Therapy, Plastic and Reconstructive Surgery 132(5): 854e-861e
