Chiropractic + Naturopathic Doctor • March/April 2022 • Atopic dermatitis

Atopic dermatitis (AD) is one of the most common dermatological conditions seen in practice in both young and older patients. Up to 17% of Canadians experience atopic dermatitis at some point in their lives (dermatology.ca, 2022). It affects 10-20% of the pediatric population and up to 3% of the adult population (Bieber, 2008). AD can present on its own, but is often a part of the atopic triad, which includes allergic rhinitis and asthma. Additionally, AD has been found to be associated with an increased risk of anxiety, depression, and suicidal ideation (Yaghmaje, 2013). A link between AD and cardiovascular conditions (cardiovascular disease, coronary artery disease, and hypertension) has been acknowledged (Silverberg, 2015).

AD is a complex condition with multiple contributing factors. A singular cause has not yet been uncovered, but rather each individual may have a varied constellation of factors that lead to their development of AD. At best, it can be considered to be a T-cell driven process with epidermal barrier dysfunction.

Keeping the diversity of contributing factors in mind, it is safe to say that a cookie-cutter approach may not always be appropriate or effective in managing AD. The integrative approach to managing atopic dermatitis takes into consideration factors that may predispose the individual to AD, factors that may exacerbate AD flares, current treatment guidelines, as well as proven alternative therapies on a case-by-case basis.

When dealing with a patient with AD, a detailed patient history is imperative. Not only will this provide the basic information needed to make a diagnosis, but also gives the practitioner clues about which therapeutic route may be most beneficial. A diagnosis of AD can be made with a detailed patient history, a physical exam of the lesion(s) including morphology and distribution, and key symptoms (Berke, 2012). The U.K. Working Party’s Diagnostic Criteria for Atopic Dermatitis is commonly used when making a diagnosis (Russel, 2001).

• A history of asthma or hay fever/ history of atopic disease in siblings and parents if the child is under 4 years

AD is a complex condition with multiple factors that can increase the incidence and further exacerbate it. These factors include: (1) genetics and family history; (2) cutaneous barrier dysfunction and increased permeability; (3) dysregulation of the immune system; (4) environmental factors; (5) digestive impairments; (6) nutritional deficiencies; and (7) stress (Maloh, 2022).

The incidence of AD in infants is 2.6 times greater when there is a documented family history of atopy (8). The genetic predisposition of AD has been extensively studied, and over 30 genetic loci have been identified (Løset, 2019). Mutations in these genes can cause immune dysregulation and disruptions in the skin barrier (8). Each mutation increases the risk of developing AD by 40-50% (Palmer, 2008). Of all the genetic loci that have been identified, the strongest genetic risk factor is due to mutations of the filaggrin gene (4).

Filaggrin is a protein responsible for collecting keratin filaments which are subsequently cross-linked to create scaffolding for the extracellular lipid matrix on the outermost layers of the dermis (38). Proper skin barrier function is dependent on a functional filaggrin gene (Maloh, 2022). In addition to aggregating keratin filaments, the breakdown product of filaggrin is a component of natural moisturizing factors (NMFs) which play a role in the skin’s ability to retain moisture and maintain an acidic surface pH (5).

Mutations in the filaggrin gene disrupt the stratum corneum, making it more susceptible to infiltration by pathogens, allergens and toxins (Kawasaki, 2012). This lays the groundwork for a chronically inflamed environment. Initially, the infiltration causes a TH1 immune response which produces inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor beta (TNFB) (Traub, 2016). The presence of this inflammation paired with increased trans-epidermal water loss (TEWL) compromises the protective effective of the skin barrier. If inflammation is present for long enough, the TH1 response switches to a TH2 response, represented by basophils, monocytes, eosinophils, and other cytokines that propagate inflammation and pruritus (Elias, 2009).

In addition to mutations in the filaggrin gene, other components that can affect the protective barrier including changes in lipid composition, increased skin pH, alterations in the skin microbiome, itching, and weakened tight junctions (Zhu, 2018).

Individuals with atopic dermatitis are more likely to experience gastrointestinal issues, such as diarrhea, and vomiting compared to a control group (Caffarelli, 1998). On the flip side, individuals with functional gastrointestinal disorders, such as IBS and constipation, tend to have a higher prevalence of atopic dermatitis compared to individuals without (45).

While there seems to be a connection between digestive system and atopic dermatitis, it is poorly understood and there isn’t enough evidence to support current hypotheses. One popular thought is that there is a link between increased intestinal permeability (or “leaky gut”) and atopic dermatitis. Cytokines that are associated with atopic dermatitis (IL-4 and IL-13) have been found to up regulate claudin-2, a protein associated with intestinal permeability (Maloh, 2022). Another association that has been explored is food allergies and AD. There are studies that suggest that a disrupted skin barrier allows for allergens to penetrate the skin, leading to increased systemic inflammation and increased sensitization for food allergens (Bergmann, 2013). Foods that are commonly associated with atopic dermatitis are peanuts, dairy, and eggs (Burks, 1998)

Various factors can decrease or worsen exacerbations, including humidity, temperature, and aeroallergen exposures.

Within the home environment, it can be helpful to keep a humidifier in the patient’s room (Gallay, 2020) and avoid air conditioning. While air conditioning hasn’t been found to worsen AD symptoms, it can weaken the skin barrier by increasing skin pH and reducing the degradation of filaggrin into NMFs (natural moisturizing factors) (Gallay 2020).

Exposure to phthalates, or a chemical additive to plastics, has also been linked with an increased incidence of AD (Wang, 2014). Phthalates can be found in multiple places within the home, including toys, food wrappings, cosmetics, and dust (Wang, 2014). It has been found that early exposure to monobenzyl phthalate is significantly associated with the development of AD (Wang, 2014). Similarly, there is a strong association with AD development and the exposure to butyl benzyl phthalate (Bornehahg, 2004). It is thought that phthalate may increase the incidence of AD because it stimulates the thymic stromal lymphopoietin (TSLP), a cytokine that triggers a TH2 response (Shigeno, 2009).

The nature of atopic dermatitis is that it is a relapsing and remitting condition; there is no cure (Weinsteine, 2020). Conventional therapies aim at minimizing and controlling flares (Weinstein, 2020) while the holistic approach aims at restoring balance within the body and removing obstacles to cure.

The first-line therapy for mild-moderate atopic dermatitis is topical corticosteroids. The appropriate agent is selected based on factors such as patient age, areas of body treated, xerosis and patient preference (Weinstein, 2020). Other options that the practitioner has for mild-moderate atopic dermatitis include topical calcineurin inhibitors and topical PDE4 inhibitors. For refractory and severe AD, the practitioner can consider phototherapy with a broad- and narrowband UVB, biologic agents in patients over 12 years old, or other systemic agents such as methotrexate (Weinstein, 2020). The practitioner must proceed with caution when selecting a systemic agent due to significant adverse effects and the requirement of regular monitoring (Weinstein, 2020).

Traditional Chinese Medicine views healing through the lens of bringing balance to the body. The underlying pattern of atopic dermatitis is the combination of heat, damp, and wind, and thus herbs that have the energetic functions of cooling, drying, and dispelling wind are used. These herbs tend to have anti-inflammatory and antibiotic properties (Chen, 2015). A common combination of herbs include Xiao Feng san - clear wind powder (Chen, 2016; Cheng, 2011). Depending on the underlying pattern of the atopic dermatitis, additional herbs can be added at the practitioners’ discretion.

The naturopathic approach to atopic dermatitis focuses on finding the root cause of the individuals’ AD, removing obstacles/barriers to healing, and supporting the body’s natural ability to heal itself. In a given patient, that may look like adding supplements/herbs/nutrient- rich foods to overcome any deficiencies and to stimulating healing; adapting the external environment to remove/reduce triggers; providing options for stress reduction; and offering topical therapies to bring relief to existing lesions.

DR. ESHA SINGH is is a naturopathic doctor practicing in Vancouver, BC. She has a clinical focus in skin health and uses an integrative approach to clinical dermatology. Dr. Esha strives to make information on skin health simple and accessible.