There is life on our skin that isn’t us, and so we are not as human as we think. Our skin is covered in an array of life forms that have only recently been brought to our attention through the use of micro technology. While the exact mechanism of psoriasis is still not clear, advances in technology have opened a world of microbia and this means we can now look at psoriasis through a new lens – literally. We already understand that psoriasis is not only a genetic condition. Current research suggests that the microbiome in patients with psoriasis is distinct from that of healthy controls.

Facts about the life forms on our skin

Around 100 trillion bacteria live in our intestines, mouth, nose, genitals, and skin by the time we are adults. Skin is an important protective barrier from the outside world and is the body’s largest and most exposed organ. Because of its size and role, human skin closely interacts with our external environment, and we have colonies of microbiota in various areas of our skin that play an important role in maintaining the function of skin barrier to suit the regions of our body. This microbiota is an array of various microorganisms, including bacteria, fungi, viruses, and arthropods that colonise the human skin and together they form the skin microbiome. The organisms in this microbiota function as either:

Commensal, meaning they colonise in harmony with us in a non-harmful way and we are most likely unaffected by the organisms however they benefit from us. A nutrient exchange may be unidirectional.

Symbiotic, meaning we need them as much as they need us for healthy function. The symbiotic relationship between us as a host and our microbiota shapes our immune system. A nutrient exchange may be bidirectional.

Pathogenic, meaning some microorganisms in the microbiota expose us to a threat of disease or lead to immune tolerance and autoimmune diseases.

Much of my research across different natural health modalities supports a belief that the ideal balance between beneficial (commensal and symbiotic) microorganisms and pathogenic microorganisms should be around 80:20. The reason given for this is that the 80% helpful little guys are being kept vigilant and resilient by the remaining 20% bad guys. Very much like your average work place or social human colony!

The role of skin microbiota on psoriasis

Psoriasis can be provoked by specific pathogens which include:

Bacteria – Staphylococcus aureus also known as “golden staph” and Streptococcus pyogenes

Viruses – human papillomavirus and endogenous retroviruses

Fungi – Malassezia and Candida albicans. [1]

Current research shows that the balance of the microbiome of psoriasis patients is different from healthy skin. We have sifted through various studies to show you the bacteria that is either more or less abundant in psoriasis skin, compared with healthy limb skin. Some studies have been contradictory and others have used only small samples of psoriasis skin so we have been careful to bring you the consistent findings of how certain bacteria loads affect psoriasis.

Bacteria more abundant in psoriasis skin

• Corynebacterium
• Staphylococcus
• Streptococcus

Alekseyenko et al. [2]

• Proteobacteria

Toscano et al [3]

Bacteria less abundant and under-represented in psoriasis skin

• Propionibacterium

Fahlén et al. [4] Ellinger et al.[5]

What we can do, now that we know this

Bringing our skin back to the right balance is one simple approach that we can adopt. While we are yet to understand the scientific basis, we can use good common sense. With a demonstrated lowering of Propionibacterium and higher levels of Corynebacterium, Staphylococcus, Streptococcus and Proteobacteria, looking at what we use on our skin may be our starting point.

The overuse of antibacterial soaps and hand gels is one change we can make today towards restoring our skin microbiome to a healthier balance. Replacing antibacterial bodywash and handwash with a gentle product such as castile soap will not only prevent the death of many of the good bacteria, but also may be more effective for hygiene than antibacterial gels.  Government health agencies including the US Centre for Disease Control advise that washing hands with soap and water is the best, most effective way to reduce the number of germs on them. When washing your hands, use plain old soap and water and rub them together for 20 seconds. Hands should be washed:

• before, during and after food handling
• before eating or drinking
• before and after caring for someone who is sick
• before and after touching a cut or wound
• after using the toilet and changing nappies
• after coughing, sneezing or blowing your nose
• after touching an animal or their waste
• after touching garbage

I am going to leave this thought here for you:

It is interesting to note that Propionibacterium, what our skin microbiome is deficient in, assists in the production of vitamin B12, and that large doses of B12 are used successfully to treat psoriasis. [6]

Our skin microbiome is closely linked to our immune system. Advances in medical technology using sequencing enables a closer look at the characteristics of how the skin microbiome is different for psoriasis patients. This is new science and an exciting new way of looking at how we can treat our skin health from the outside.

Reference

 [1] Fry L, Baker BS. Triggering psoriasis: The role of infections and medications. Clin Dermatol. 2007;25:606–15. doi: 10.1016/j.clindermatol.2007.08.015

[2] Alekseyenko AV, Perez-Perez GI, De Souza A, Strober B, Gao Z, Bihan M, et al. Community differentiation of the cutaneous microbiota in psoriasis. Microbiome. 2013;1:31. doi: 10.1186/2049-2618

[3] Drago L, De Grandi R, Altomare G, Pigatto P, Rossi O, Toscano M, et al. Skin microbiota of first cousins affected by psoriasis and atopic dermatitis. Clin Mol Allergy. 2016;14:2. doi: 10.1186/s12948-016-0038-z. 

[4] Fahlén A, Engstrand L, Baker BS, Powles A, Fry L. Comparison of bacterial microbiota in skin biopsies from normal and psoriatic skin. Arch Dermatol Res. 2012;304:15–22. doi: 10.1007/s00403-011-1189

[5] van Rensburg JJ, Lin H, Gao X, Toh E, Fortney KR, Ellinger S, et al. The human skin microbiome associates with the outcome of and is influenced by bacterial infection.  MBio. 2015;6:e01315. doi: 10.1128/mBio.01315-15. 

 [6] Ruedemann R. Treatment of psoriasis with large doses of vitamin B12 1,100 micrograms per cubic centimetre Preliminary Clinical Report. AMA Arch Derm Syphilol. 1954;69(6):738–739. doi:10.1001/archderm.1954.01540180088013