How can we reconcile our understanding of Atopic Dermatitis from the perspective of both Western Medicine and Chinese Medicine?
Atopic dermatitis can be said to be due to two main dysfunctions, both related to a genetic disposition. There is a situation of a weakened skin barrier and on top of that, an imbalanced (read: over-reactive) immune system.
Traditional Chinese Medicine has documented the existence of eczema-like diseases as early as the Han dynasty, during the time of Christ. Jin Yin Chuang was seen as an infiltration of outside pathogens. In fact, different names were given for skin lesions appearing in the face, the flexures, the genital regions, the ankles as well as other parts of the body. TCM understands it this way: that the body has a weak exterior and that there is accumulated heat in the organs.
Atopic Dermatitis (AD) is commonly known as Eczema. When we speak about the “causes” of AD, we can only point to two categories.
Epidermal Barrier Dysfunction:
The first category is epidermal barrier dysfunction.
One reason for this is a well-documented genetic defect in filaggrin, a protein that helps in the formation of the stratum corneum. The stratum corneum is the uppermost layer of the epidermis and is a barrier against possible allergens, microbial incursions as well as other foreign substances. Lack of sufficient filaggrin to bulk up the skin barrier is also related to non-‘skin’ presentation of atopy, e.g. allergic rhinitis and asthma.
People who suffer from AD often suffer from increased transepidermal water loss (TEWL), decreased water binding (humectant) properties and reduced surface lipids e.g. ceramides. They also present with dysfunction in the production of antimicrobial peptides and in the molecular recognition of invading pathogens.
The earlier methods of topical treatment involved the use of emollients and humectants to bind in water and keep the water in. This is the moisturizing aspect of treatment.
The intercellular lipid matrix of the stratum corneum,consisting of ceramides, cholesterol and fatty acids, is also compromised, and so there came to be created more sophisticated products, each hoping to deliver enhanced moisturizing effect with exogenous delivery of ceramides, squalene and natural lipids of all forms.
In flare situations, there is first of all a clear presence of inflammation and possible microbial colonization, often with staphylococcus aureus.
Immune System Imbalance:
The secondary category is an ‘imbalanced’ immune system. To understand this imbalance better, we need to understand our cell-mediated immune response.
Cell-mediated immunity uses T cells (aka T lymphocytes), whose receptors recognize foreign bodies, and follow up by calling in the cytokine troops begin a cascade of immune reactions to help protect the body.
There are 2 categories of T cells: T Helper cells (aka CD4 expression T cells) and T Cytotoxic cells (aka CD8 expression T cells). We are interested in T Helper cells here.
T Helper cells then produce Th1 and Th2 cytokines. The issue with persons plagued with atopy is the Th2 cytokines are upregulated in relation to Th1 cytokines, and elevated Th2 cytokines are associated with IgE-type responses, tissue eosinophilia, mast cell hyperplasia, and producing symptoms like catarrhal inflammation (watery mucus production) and hyper-responsive airways (e.g. in asthma).The irony is that Th2 cytokines are predominantly anti-inflammatory (as opposed to Th1 cytokines that are pro-inflammatory). The “water” of Th2 cytokines are supposed to help douse out the “fire” of Th1 cytokines, but end up causing a different type of problem in atopic individuals.
It is not that difficult to reconcile the idea of epidermal barrier dysfunction with ‘exterior weakness’ in TCM. As for the broad concept of an imbalanced immune system, Chiense Medicine calls it ‘accumulated heat in the organs’ and it is to show that this accumulated heat is waiting to express when triggered.
Hence, most treatment regimes will include one or all of moisturization, anti-inflammation and anti-microbial treatment.
In terms of topical treatment, if you look at the range of products out there, the anti-inflammation comes from topical steroids, and the anti-microbial is often systemic use of antibiotics.
From the viewpoint of an herbalist, the added natural ingredients in some products are often understood within the Traditional Chinese Medicine framework as ‘heat-clearing herbs. Examples include calendula, neem, coptis. And their supplement counterparts include but are not limited to the antioxidant vitamins A, C and E.
Oils are often used for moisturizing purposes and from the traditional medicine viewpoint, these are yin enhancing and would include omega fish oils, coconut oil, jojoba oil, olive oil, and so on.
If the patient also presents with serous exudate, also known as oozing to the layperson, then herbs that clear damp are also added in. These include sophora root, poria and plantago seed.
Treatment from the point of TCM is focused on resolving the exterior with herbs like ledebouriella root, schizonepeta stem or bud or even the shedded skin of the cicada. Yin enhancers may include herbs like rhemannia, lily bulb, scrophulariae root, etc. And then there are also herbs that aid blood circulation too.
While some drugs like MTX and cyclosporine are sometimes prescribed to help suppress an ‘overactive’ immune system, Chinese medicine seeks to create a balance with the help of herbs. This balance is often dependent on the presentation of the patient, and after assessment of history, tongue and pulse diagnosis, as well as observing the skin as it presents itself, herbs are prescribed. During a flare state, herbs will be prescribed that possess anti-inflammatory and anti-microbial function. But there will also be herbs to help with balancing out the entire immune system.
Now, we move on to the concept of triggers.
A barrier dysfunction is likely to predispose to a certain kind of sensitivity. Sensory nerve fibres are more easily irritated by temperature changes, exposure to soaps, detergents and even changes in humidity of the environment. Allergens may be transmitted through the air (e.g. dust, perfume, cigarette smoke), through pets (e.g. cats and dogs), mite exposure, and last but never least, food.
An immune system predisposed to atopy-type reactions means that a cycle will start to build up. The skin reacts to external incursions by producing proteases and histamine, which result in the feeling of itch. Scratching relieves the itch but causes additional inflammation while also aggravating barrier dysfunction. This results in a vicious cycle where the skin presents with erythema, serous exudation, crusting and scaling, where some recovery is then disrupted by further skin damage and a form of immune reaction that only damages the skin even more.
In addition to the triggers listed above, there are triggers that clearly weaken and unbalance the immune system further. The greatest two disruptors are psycho-emotional stress and lack of restful sleep.
Strengths & Weaknesses of Chinese Medicine:
I would think that the strength of Traditional Chinese Medicine in the treatment of AD is (1) during the onset of a flare; and (2) for maintenance.
The multi-pronged attack by the numerous anti-microbial and anti-inflammatory herbs in a formula may not be as strong as a single steroidal compound, but just because it is not a single strong compound means there is less basis for the building of resistance or tachyphylaxis.
The herbal formula is revised, consultation after consultation, depending on how the patient is presenting at a particular point in time. This means that if the erythema phase component is not as severe, but now if oozing has started, the herbs can be changed to tackle the changing presentations. It is a very flexible form of medicine.
In the chronic stages, a lot of emphasis is on modulating immune function with diet and foods, all of which help to ‘balance’ out a genetic disposition toward ‘immune system imbalance’.
Already in the past, Chinese medicine has identified triggers, both from contact and also from food. Seafood has been easily identified as a trigger, as are bamboo shoots and duck. However, if we are to move toward a more personalized form of medicine, then the list of food triggers can only be a reference list. The same for lists created within the Occident, e.g. dairy, sugar, peanuts, nightshades, wheat, etc. They may apply to many, especially to atopic individuals with a high level of food intolerance, but it does not apply across the board.
Challenge testing is a great concept to learn from the Occident; as are skin prick tests and serum blood testing, which, while laden with false positives and negatives, may point the patient in the right direction for food otherwise difficult to identify as a trigger.
There is also that comprehensive framework on gut health developed by the naturopathic community over the last 150 years. The benefits of using commercially-prepared or food-source probiotics is only the most well-known form. There are other therapeutic tools used by the naturopathic community that are also immensely useful for those suffering from atopic dermatitis.
Holistic Inclusion of Other Interventions:
Apart from using the herbs personally mixed for their consumption, and undergoing acupuncture treatment for high-response areas or lesion-types, the treatment approach should be well-rounded that includes these other interventions: