The human body is an ecosystem populated by trillions of bacteria, viruses, and fungi. All these microorganisms and their genome form the so-called human microbiome. In our body, we host 10-100 trillions of microbial organisms - and we do so for the whole of our life. Scientists calculate that humans live with ten times more non-human cells than human cells and that these cells are able to express 100 genes for every single gene we produce.
Every area of our body hosts a different microbial community. Our armpits and brow are the most densely populated, but also the most homogeneous. On the contrary, ,we may identify on our palms a great number of different microbial cells, although much lower in number.
Research showed that a well-balanced microbiome is crucial for human health, as it plays a role in protecting us from many inflammator, metabolic and allergic diseases.
When human microbiome is altered either in quantity or in proportion (that is, the global amount of microorganisms forming a specific microbiome or the relative size of the different microbial population's change) the organism enters in a state of dysbiosis.
Knowing the exact composition of the microbiome on skin and scalp could help for treatment of skin and hair disorders; this helps us to restore or maintain a balanced microbiome, simply acting on diet, lifestyle or with specific therapeutic treatments that positively affect our health.
Also the skin hosts a specific microbiome – same as the guts, and as much as important for our health. Among the different microorganisms living on the skin , the most common and widely known is the Propionibacterium acnes, which causes acne in predisposed subjects while remains innocuous to others.
Another very common microorganism is the Staphylococcus epidermidis, which is able to hinder the growth of another microorganism, the Staphylococcus aureus, also very common on our skin. When the Staphylococcus aureus grows abnormally, it may cause various diseases.
Disbiosys of microbiome seems to be the major cause of inflammatory diseases of the skin, such as atopic dermatitis and psoriasis.
Skin and bowel diseases have long been knowing to be connected. Both skin and guts are key to protecting us from external pathogens. Furthermore, they act as mediators in the neuroendocrine transmission.
Progresses in the techniques of DNA sequencing allowed a throughout examination of the microbic communities, thus enabling us to get a complete map of the human microbiome.