As the eyes are the reflection of one's inner health...they are literally as we know a window into a person's vascular and neurological system as the only location in the body where the nerves and vessels can be seen without invasion. Yet, an even more profoundly evident barometer to one's overall health happens to be the largest single organ in the human body that is visible. The skin ranges in thickness from one to two millimeters and varies from 0.6 millimeter on the eyelid to three millimeters on the soles and palms. It comprises approximately 12-15% of total body weight and has a surface area of 1-2 meters.

The skin consists of two distinct layers, the outer layer (epidermis) and the thicker underlying layer (dermis). The epidermis and the dermis differ in function, appearance, and origin. Beneath the innermost layer, the subcutaneous layer (hypodermis) binds the skin to the underlying structures such as the hair, nails, and sweat glands. Collectively these structures are considered appendages of the skin, as they are all of epithelial origin. The skin serves as a physical barrier to protect the inner body from foreign matter while also providing protection for the internal organs and maintaining moisture within the body. The skin also plays a large role in the homeostatic changes that affect the body such as temperature regulation, sensory reception, biochemical synthesis, protection, absorption, and elimination or detoxification. Receptors in the skin include those for pain, pressure, and temperature. Meissner's corpuscles are sensitive to touch, and Pacinian corpuscles are sensitive to pressure. Specialized skin cells also synthesize melanin and carotenes, which serve as pigmentation sources and production of vitamin D.

We often judge the health of our pets by the appearance of their coats, if they are shining and smooth it is said they have a healthy coat and is considered a reflection of their overall well being. So, whether it is our hair, nails or skin, human skin also reflects our health as individuals. We have all seen friends and family that look pale, drawn, and ashen, all reflective of overall internal balance. Additionally, observing the skin through various disease processes can sometimes serve as a measurement on the continuum of health along which the patient is progressing. Homeopaths and Naturopathic physicians are taught Hering's Law of Cure, which state that a patient's signs and symptoms of disease will disappear from within outward and in the reverse order of their appearance, and that the body seeks to externalize disease as part of the curative process.

Even as holistic physicians we have to find the balance between helping patients deal with the immediate social consequences of skin problems, while addressing the deeper underlying causes and factors that have led to the susceptibility that results in the overt signs of eczema, for instance. Few people are born with eczema, and many times eczematous bouts come and go, during a person's life. By evaluating which triggers are present, nutritional factors and deficiencies, and external factors such as irritants are all important. After all, the good physician blends the best of science, nature and good old-fashioned detective work. So, going back a couple of weeks to months prior to the outbreak or flareup often points to the true and deeper issues at hand that has so disturbed the innate health and homeostasis of the body that it has begun to complain in one of the most obvious of all manners — with a skin manifestation. The concept of treating eczema with hydrocortisone or other suppressive therapies is inherently foreign to the holistically minded physician. Doing such, though palliative, equates to no less than turning a blind eye to the problem and then believing all is good and well.

Causation
Studies involving the use of double-blind, placebo-controlled food challenges show that upon repeated exposure to a known food allergen, eczematous lesions can result in susceptible patients. The most common foods that exacerbated the eczema in these patients were…cow's milk, eggs, wheat, soy peanuts, eggs and fish.¹ Removal of these foods from susceptible patients' diets resulted in remission of eczema symptoms.² The food allergy-eczema link is well established, and the most common-sense approach to this association is allergen avoidance. However, avoidance of foods is not the entire solution, and new studies are exploring other theories of eczema causation. Atopic dermatitis is also affected by exposure to other allergens, which follows the pattern of most atopic individuals suffering from asthma, allergies and eczema. Allergens such as dust mites, animal dander, and pollens are known to worsen and bring about an eczematous flare up. Seemingly ubiquitous, these aeroallergens can be somewhat controlled in the home environment, allowing for clinical improvement of the patient.³

Another link in the development of eczema may lie in an improperly functioning epidermal barrier that exposes the patient to rapid dehydration of the skin due to its inability to retain water, resulting in shrinking and gapping of the epidermal barrier. Epidermal barrier dysfunction has many suspected causes, and several studies have implicated psychological stress as a negative influence on cutaneous barrier function, and may trigger or aggravate skin disease.⁴ Researchers implicate increased glucocorticoid production, resulting from stress, as the main factor that causes epidermal permeability homeostasis. Interestingly, histamine, a body chemical widely implicated for its role in allergic reactions, has been shown to delay epidermal barrier repair.⁵ Keratinocytes, a type of skin cell, have histamine receptors on them, but their functions are poorly understood at this time. In the same studies, it was noticed that the use of histamine agonists, which activate the histamine receptors, slowed skin repair while histamine antagonists, which block the effects of histamine in the body, allowed for accelerated recovery of skin barrier function.

Prevention
Perhaps the greatest opportunity for disease prevention occurs in the earliest stages of life, prior to birth and immediately after, when the human body is most "impressionable" to external influences and their role on the body's defenses.

Probiotics
New research surrounding the use of probiotics in the prevention and treatment of eczema in the unborn is extremely enticing. Probiotics are food supplements comprised of billions of live microbial organisms that have numerous beneficial effects on human health, and may be used both prophylactically and therapeutically. Certain strains have demonstrated powerful anti-pathogenic, anti-inflammatory, and anti-allergic effects. The early composition and subsequent development of the gastrointestinal microflora is now considered a pivotal determinant of both normal gut barrier function (relating to food allergy) and phenotype of immune response. (It is postulated that signature allergic inflammatory processes are expressed as a result of unbalanced Th1 and Th2 cytokine production, with a dominant polarization toward a Th2 phenotype, of which atopic disease is well-known to be Th2-mediated.)⁶ Subsequently, a significant improvement in the clinical course of atopic eczema has been reported in infants given a probiotic-supplemented diet.

The potential of probiotics to reduce the risk of atopic disease has been graphically demonstrated in a double-blind, placebo-controlled study in which probiotics administered pre- and postnatally for 6 months to mothers at risk for eczematous disease, reduced the prevalence of atopic eczema to half of that observed in infants receiving placebo.⁷ Maternal atopy is a clear risk factor for atopic eczema in the infant. Administering probiotics during pregnancy and breast-feeding offers a safe and effective mode of augmenting the immunoprotective potential of breast-feeding and provides protection against atopic eczema during the first 2 years of life.⁸

Hygiene hypothesis
The hygiene hypothesis postulates an inverse relationship between hygiene, in its broadest sense, and allergic disease. This theory suggests that atopic disease may arise from a lack of counterbalancing microbial exposure at an early age. Recent studies suggest that many hygiene related factors might influence immune development in favor of an allergic phenotype. Antibiotics in the early stages of life have been associated with increased risks of allergic disease in later childhood, while farming exposures lead to protection. The role of bowel flora in modifying immune development has been suggested as an explanation for the risk associated with antibiotic exposure and has led to various studies exploring the effects of bowel flora modification with probiotics — both to influence established allergic disease and to prevent it. Recent findings from these studies indicate alterations in intestinal microbial concentration are common in infants suffering from allergic disease and those that develop atopy at a later date, and that probiotic supplementation strengthens gut defense barrier mechanisms and reduces antigen load in the gut mucosa.⁹

Breast Feeding
Exclusive breast feeding in only the first few weeks after birth exerts positive effects on the incidence of allergic and infectious disorders. In newborn siblings of children with atopic disease exclusively breast-fed for only six weeks, the incidence of eczema, recurrent wheezing, elevated serum IgE-antibodies to cow's milk, complement activation in vivo after milk challenge and hemagglutinating antibodies to beta-lactoglobulin was significantly lower compared with formula-fed matched group.¹⁰ On the same page, however, infants that are susceptible to atopic disease can develop eczema from the transfer of allergy-inducing antigens in breast milk.¹¹ Therefore, it is equally important that the mother's diet be free from as many suspected food allergens as possible while breast feeding, and that breast feeding continue for several weeks postnatally. Because of the strong link between antigens in breast milk and the occurrence of atopic skin disease in the infant, it is strongly recommended that serum testing for food allergens be performed prior to birth, on the mother.

GI integrity
Integral to the treatment of the eczematous patient is an approximation of gastrointestinal integrity. The concept of "leaky gut" runs through the principles of practice for Naturopathic physicians treating patients in which defective intestinal permeability plays a role. If the eyes and the skin are the portal through which we may observe the body's internal health, the gut then is the door through which a majority of disease initiates its entrance into the body. It goes without saying that many factors in today's lifestyle compromise the meticulous integrity of the gut lining, namely food choices and antibiotic therapies.

The first area of treatment then for the patient displaying eczema should be the gastrointestinal lining, without a doubt. Indigenous gastrointestinal microbes have a significant effect on the gut-associated immune system and play a large role in the development and maintenance balance between tolerance to innocuous antigens and capability of mounting an inflammatory response towards potential pathogens. Distinctive alterations in the composition of gut microbes appear to precede the manifestation of atopic disease, which suggests a role for the interaction between the intestinal immune system and specific strains of the microbes in the pathogenesis of allergic disorders.¹² Restoration of intestinal permeability, unbalanced gut microecology, improved immunological gut barrier function, and down-regulation of intestinal inflammatory responses with reduced pro-inflammatory cytokine production are the goals of gastrointestinally focused therapies for eczema treatment.¹³

Conclusion
Wide arrays of natural therapeutics exist to treat the symptoms of eczema, however by looking into the underlying causes of the disease's manifestation, treatment becomes more applicable and multidimensional. Clearly, suppressive therapies (hydrocortisone) for eczema only serve to prolong actual treatment of the symptoms. Natural therapeutics may be considered equally palliative as we learn more about the role of the gastrointestinal system and immune function in this condition. Studies of probiotic supplementation in pregnant women bring new light to "treating the cause," as the treatment is directed at preventing the occurrence of a disease condition in a future patient! A classical naturopathic therapeutic approach entails "treating the gut" in a number of disease conditions, and like so much of natural medicine, scientific research continues to validate what Nature has known all along.

Correspondence:
Chris D. Meletis, ND
Dean of Naturopathic Medicine
Chief Medical Officer National College of Naturopathic Medicine
cmeletis@ncnm.edu
503-499-4343 #1620

Jason Barker, ND
Second Year Resident, NCNM
jasonebarker@msn.com
503-499-4343 #1811

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