Written by Kiera Nikolakakis
The prevalence of inflammatory skin conditions has dramatically increased over the past few decades. There is emerging research on the connection between the microbiome of the gastrointestinal tract and inflammatory skin conditions.
This leads to suggest that where there may be skin inflammation present – this may be an indication of inflammation within the gut lining and dysbiosis of the microbiota.
What is the ‘Gut Skin Axis’?
Our skin and gut are home to trillions of microbes that create the microbiota. Research suggests that the microbiome of both the skin and gut are directly linked which is known as the “gut-skin axis”.
This is due to the immunological and metabolic processes of the gut, known as the gut microbiota, one of the main influences of the ‘gut-skin axis’. Essentially, dysfunction of the gut microbiome disrupts the skin microbiome which emerging research is now linking to inflammatory skin diseases commonly seen in Dermal Clinicians; practice such as atopic dermatitis and acne.
What is the Gut Microbiome?
The Gastrointestinal Tract contains all of the major organs of the digestive system including the intestines. It’s fascinating that this houses a multitude of species essential to survival such as varying fungi, viruses, protists, archaea and primarily bacteria. This collectively forms the gut microbiome.
The complex array of biological and metabolic functions held in the gut microbiome as well as environmental factors, such as diet and lifestyle, modulates the phenotype of the host.
Good bacteria help with the metabolism of nutrients from some of the foods that our intestines can’t manage to completely digest, which in turn aids with nutritional absorption, improving the body's immune function whilst also supporting the integrity of the intestinal wall.
Connecting Gut Health to the Skin
An abundance of bad bacteria can contribute to skin health problems. Similar to the gut, the skin also has a microbiota, made up of a large variety of diverse organisms.
Dysbiosis is the imbalance of gut bacteria, which we now know also disrupts the skin's ability to efficiently perform vital functions like temperature regulation, protection and the ability to retain water. Dysbiosis of the gut alters the skin microbiome, essentially leading to exacerbating influence on inflammatory skin conditions.
The skin is constantly regenerating itself via epidermal cell turnover, which is an essential function in maintaining a state of homeostasis. Although it is difficult to find a definitive cause-and-effect relationship between the gut microbiome and inflammatory skin conditions, research now shows that the gut microbiome affects both the cutaneous microbiome and homeostatic balance. This is an important concept to understand and consider as Dermal Clinicians when treating and educating patients with inflammatory skin conditions. Essentially, bacteria are in the driver’s seat and the skin is in the passenger’s seat.
The microbiome is one of the prime controllers of the immune system, supporting cutaneous homeostasis.
The skin microbiome has recently gained a lot of attention. Research suggests that some inflammatory skin disorders are now linked to the gut-skin axis. This includes research on:
Atopic Dermatitis
Atopic dermatitis is a chronic inflammatory skin condition with a multifactorial pathogenesis. This involves an altered innate and adaptive immune response, dysfunction in epithelial cells of the epidermis, multiple potential inherited gene mutations, as well as environmental risk factors. However, studies have also now
suggested that atopic dermatitis is associated with the gut microbiome.
The microbiome is made up of a multitude of opportunistic organisms. In terms of the gut microbiome, those with atopic dermatitis can have higher levels of species like Faecalibacterium prausnitzii, Clostridium, and Escherichia (in infants) and lower levels of Akkermansia, Bacteroidetes, and Bifidobacterium. In terms of the skin microbiome, there is a decrease in the diversity of bacteria and an increased abundance of s.aurus, which is a form of pathogenic bacteria. These distinct microbiota characteristics show a correlation between a dysfunctional gut microbiome and atopic dermatitis.
Acne Vulgaris
We all know that acne is a very common skin condition and over the years has been largely researched with a wide variety of causes that vary in each individual. There are now studies on the skin and gut microbiome (and more specifically, gut dysbiosis) as one of the causative factors of the condition.
Cutibacterium acnes (c.acnes) is a type of bacteria found in those with acne, but is also found in the microbiota of non-affected, healthy skin. However, in acne skin, there is a pattern of some particular c.acnes strains, indicating a change in the skin microbiome of those with acne. In terms of the gut microbiome, there has been a large number of studies that link gut dysbiosis to this inflammatory skin condition, however, many different types of gut dysbiosis have been observed.
As practising Dermal Clinicians, it is imperative to understand that not all individuals with acne vulgaris have gut dysbiosis, however, it is just one of the possible causative factors of the condition and must be initially considered and investigated.
How Dermal Clinicians can Educate on the ‘Gut-Skin Axis’
It may be best practice for Dermal Clinicians to share this research with their patients, and encourage them to do their due diligence in seeking support from other appropriate allied health or medical practitioners who specialise in clinical investigation and treatment of gastrointestinal dysbiosis as a part of their scope of practice.
Written by Kiera Nikolakakis. Reviewed by the Education Sub-Committee of the Australian Society of Dermal Clinicians.