INL Articles - Eczema and the Lymphatic System
Eczema, the Microbiome, Detoxification and the Lymphatic System
According to the Hong Kong Allergy Association, one in five people have at some stage experienced eczema or eczema related symptoms such as itchiness, blistering, redness and swelling.
Options for treatment are generally restricted to topical steroids, antibiotic treatments and moisturisers for dry skin. It seems that the chronicity of eczema and its increasing prevalence amongst adults and children means that whilst symptomatic relief of this condition is easily accessible, the root cause of why it is there in the first place may not be covered leaving less longer-term amelioration for patients.
The digestion and the microbiome can play a role from early life
With 70% of the immune system residing in the digestion, specifically the gut-associated lymphatic tissue, researchers are now investigating how the microbiome and its commensals influence immunity at distal sites of the body such as the lungs, brain and the skin. This has led to the creation of terms common in functional and natural medicine such as “gut-brain axis” and “gut-skin axis.”
Whilst some eczema symptoms can present later on in life, the majority of the harder to treat conditions occur during early life. It’s suggested that the microbiome within the digestion plays a major role in the development of eczema via the regulation of the innate and adaptive immune system’s maturation through crosstalk between the microbiome and the host. (1)
This occurs via bacterial metabolites mediating communication between commensal bacteria and the immune system, affecting the balance between pro and anti-inflammatory mechanisms such as TH17 and T-regulatory cells. (2)
As research has continued we now have evidence that the proportion of Clostridia, Clostridium difficile, Escherichia coli, and Staphylococcus aureus (S.aureus) in the gut microbiome is higher than in healthy controls when it comes to eczema. Whereas, the level of Bifidobacteria, Bacteroidetes, and Bacteroides is decreased. (3)
Interestingly the presence of Clostridia and Escherichia coli in the intestine may be linked to the development of childhood atopic dermatitis via eosinophilic inflammation. (4)
A study released in 2016 also investigated the role of short chain fatty acids and their relationship with bacteria such as Akkermansia muciniphila, Faecalibacterium and Bifidobacterium. When looking at neonatal microbiota samples in early life, it was found that dysbiosis levels at this young age might promote T-cell dysfunction associated with atopic conditions such as those associated with eczema. (5)
The connection between detoxification and the lymphatic system also compounds the problem
A study conducted in Hong Kong in 2019, investigated the role that heavy metals can have on the pathogenesis of eczema along with other pollutants such as air pollution. Measuring cadmium, lead, mercury, selenium, copper and zinc levels in 110 patients with eczema all six of the heavy metals measured were in the higher limits of the local Hong Kong reference range, well-known to be higher than other regions of the world. Most significantly, lead levels were considered to have noteworthy correlations to atopy, quality of life and symptom severity in the subjects studied along with low levels of zinc and copper commonly found across all groups. (6)
Initial studies have now also connected a reduction in heavy metal exposures such as lead and management of the microbiome and the fight against antibiotic resistance in cases of nasal S.aureus and MRSA, commonly seen with infective eczema. (7)
From here we can now see the gut-associated lymphatic tissue and the lymphatic system in general get loaded up with the skin being one of the first sites to express it in the form of inflammation.
It is for this reason that natural medicine interventions for eczema often involve a significant number of herbs that can both circulate and improve lymphatic status often over the course of 12 weeks leading to better outcomes.
Probiotics and microbiome modulation can play a vital role in the prevention of atopic eczema but in a different way than you may think
Probiotics have been well-documented to stimulate the T-regulatory cells that can help bring balance the Th17 imbalance seen in eczema. They have also been found to regulate allergic hypersensitivity by suppressing the Th2 mediated immune response via this stimulation of T-regulatory cell production. (8)
With Lactobacilli spp. being at the forefront of addressing the gut-skin axis, species such as L.rhamnosus have been shown to reduce the occurrence of atopic dermatitis in infants by 39%, with an important note from the study demonstrating only a small reduction in symptom relief. (9)
More recent studies have suggested that L.rhamnosus HN001 supplementation may in fact offer preventative benefits beyond the earlier years potentially extending to 11 years old. Published in 2018, this was the first early probiotic intervention that demonstrated positive outcomes for at least the first decade of life in not only eczema but across the allergic disease spectrum. (10)
Another important outcome from these studies suggested the aforementioned outcomes may actually be species specific. A double-blind placebo controlled trial looking at L.rhamnosus HN001 and B.lactis HN019 on eczema prevalence and atopic sensitisation showed significant results with the L.rhamnosus HN001 group without the same effect occurring in the B.lactis HN019 group.
Interestingly innovative ways to modulate the microbiome for eczema are showing promise via the neuroendocrine molecules produced within the digestion. For example, tryptophan produced by the gut microbiome produces an itching sensation in the skin (11), whereas Lactobacillus species and Bifidobacterium species can produce GABA which has been shown to inhibit skin itching. (12) Furthermore, Escherichia species and Enterococcus species can produce serotonin, which is involved in skin pigmentation. (13)
Another element within this landscape is the upregulation of neuropeptides such as Substance P. This plays an important role in eczema both as a pro-inflammatory mediator via the stimulation of keratinocytes as well as its effect on mast cell degranulation. Substance P has also been a key therapeutic target because of its role in itching, a key treatment goal in the management of eczema. (14)
Neuropeptides like Substance P are of great interest due to their proposed ability to exert an effect across many different organs as communication conduits between gut bacteria and other tissues and organs. There is even some evidence pointing to their anti-microbial action within the digestion, in particular levels of Escherichia coli, discussed previously to have a role in the development of eczema. (15)
This relationship is being explored further with Gueniche’s research on the role that L.paracasei can play in the inhibition of substance P-induced skin inflammation leading to a potential therapeutic option in speeding up skin recovery. An initial pilot study in-vitro showed that the application of L.paracasei was able to attenuate the vasodilation, oedema, mast cell degranulation and TNF-alpha release induced by substance P in comparison to controls. (16)
This study was then built upon in 2014 with a randomised double-blind controlled trial with a human cohort where oral supplementation of the same species decreased skin sensitivity and increased the rate of barrier function recovery offering promise in reactive skin conditions as well as eczema. (17)
In conclusion, the road towards the management of eczema seems to be a long one but hopefully this article goes some way to highlight some of the more innovative and evidence directed methods practitioners can take from both a symptom management and preventative point of view.
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