This is a very interesting topic because it represents a major paradigm shift to how we view allergy – it’s not just what we eat (oral path) but also what’s on our skin. It is now accepted that what is on our skin can lead to sensitization and allergy. For instance, dermatologist Cheryl Lee MD said in this post:
When allergens come in contact with the skin, then the allergic type of inflammation is turned on. On the other hand, it has been shown that if you can avoid letting allergens (including foods!) from coming in contact with the skin long enough, then your child’s immune system will build up tolerance to the food when it is presented to the immune system of the gut. What this tells us is that, in susceptible populations, the skin barrier needs a little help as it is maturing.
Let’s take a closer look at this article published in Aug 2014 in Journal of Allergy and Clinical Immunology by Japanese researchers.
This is an article that looks at the studies being conducted, and it’s not exactly recent but I like it because it reinforces the understanding of outside-in hypothesis.
Link between Food Allergy and Eczema – From the Skin
Researchers started to look at the link between our skin and food sensitization because studies (quoting this article) demonstrated that exposure to environmental peanut protein–containing household dust and use of hydrolyzed wheat protein–containing soap significantly increased the risk of allergic sensitization to peanut and wheat, respectively. In addition, filaggrin loss-of-function mutations were a significant risk factor for peanut allergy. Those findings strongly suggest that epicutaneous exposure to proteins induces allergic sensitization…
presence of eczema is a robust risk factor for allergic sensitization to food antigens and development of food allergy
It is compiled in the article that increase in skin pH, scratching and impaired filaggrin are factors that lead to food sensitization. We have talked about the importance of skin pH for the whole of December last year and in summary, skin that is too alkaline is linked to reduced ceramides, skin lipids (good for our skin) and increase in staph bacteria (bad for our skin). Foods that come into contact on our skin can certainly trigger eczema flare-ups too!
My take: Strengthen the skin barrier – moisturize, use right products of optimal skin pH and without common irritants, treat skin promptly to reduce scratching. Keeping eczema under control or moisturizing to prevent eczema onset can have a real chance of preventing allergy.
What’s your take? Do share your take in the comment so we all can hear from each other!