Dermatology

Skin and Allergies

Understanding and appreciating your skin as a barrier is essential to maintaining skin and body health.

The skin’s role in our immune system must be recognized. The skin is essentially the “first line of defense” between our bodies and the external environment. As such, our skin is exposed to many potential harmful exposures including pollution, irritants, ultraviolet radiation, chemicals, and natural compounds. When the barrier of our skin isn’t working at full capacity, the potential for these external factors to harm our skin and “irritate” our immune system increases. This can result in allergies, skin infections, inflammation, eczema, and contact dermatitis.

Think of your skin as the filter between your internal body and the world around us. In a sense, the skin is the means by which the external environment communicates with our internal selves. The skin is a complex organ, comprised of the stratum corneum that sits above the epidermis, the epidermis, dermis, and subcutaneous fatty tissue.

The skin barrier includes the microbiome, physical elements, chemicals, and immune layers. The microbiome is a very active and dynamic community comprised of living bacteria, yeasts, viruses, fungi, mites, parasites, and other organisms that are constant communication with each other, our internal body, and the world around us. The skin microbiome has been actively discussed in recent research regarding skin health as we start to recognize the complexity of this entity, and the importance of protecting and nurturing it to keep our skin and our bodies healthy. The chemical layer has natural moisturizing factors and other chemicals that maintain the pH of our skin. The physical part of our skin barrier is just that: the cells and connections among them that actually form what we recognize as tangible skin. Finally, the immune portion of our barrier is made of microscopic immune cells that are essentially scouring our skin like little police peacekeepers.

Our skin has a remarkable ability to stay balanced and stable in regard to all of these elements. The microbiome communicates closely with the immune cells. When the microbiome is disrupted, the skin barrier is consequently threatened. In practice, this translates to an awareness of keeping our skin clean and healthy, without stripping or harming the little organisms that are so essential for keeping our skin, and our bodies, in balance. While we want to wash away dirt, oil, and other skin irritants, we also need to support the helpful community of bacteria, fungi, etc on our skin. Similarly, our chemical skin barrier stays balanced when we maintain an optimal skin pH between 4-6. The physical barrier of our skin actually protects us from the entry of foreign substances such as chemicals, irritants, harmful bacteria, etc. Thy physical barrier must stay strong, without cracks, breaks, or openings that would allow foreign materials in. And the immune portion is closely integrated within all of the other components of the skin barrier, communicating among the external pathogens, and the other cells of our skin and our bodies.

In dermatology, we recognize the following:

  1. When the skin barrier is disrupted, this can lead to allergic sensitization
  2. When the skin barrier is repaired, this may prevent allergic sensitization
  3. Allergies can develop through skin sensitization
  4. When the skin barrier is compromised, allergies can develop
  5. Skin barrier disruption can result in contact dermatitis
  6. Proper skincare plays a critical role in keeping the skin barrier strong, healthy, and protective

Emollients can aid in repairing the skin barrier by restoring water and lipids and also promoting ceramide synthesis. When the lipids are replaced, inflammation is reduced. Barrier creams and ointments essentially create a protective layer over the skin, thereby preventing entry of environmental irritants and also preventing the loss of water from within our skin into the external environment.

There is also increasing recognition regarding skincare products that support of the microbiome of the skin. These washes, creams, and serums regulate inflammation to support the healthy natural flora of the skin. Prebiotics may be added to skincare products and may have a role in creating a diverse and optimal microbiome. The ideal skin mositurizer would avoid preservatives that can damage the microbiome, have an neutral pH to support the skin pH of 4-6, avoid allergens and fragrances that could aggravate the skin. As with most things in life, there is give and take that is required in each of these categories in order to create an effective, sustainable, cosmetically elegant and attractive product.

Strugar TL et al. Connecting the Dots: From Skin Barrier Dysfunction to Allergic Sensitization, and the Role of Moisturizers in Repairing the Skin Barrier. J Drg Dermtol 2019 18(6): 581-586

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