By Robert Preidt
The breakdown in the skin barrier that occurs in eczema could play a key role in triggering food sensitivity in babies, the researchers from King's College London and the University of Dundee said.
"This is a very exciting study, providing further evidence that an impaired skin barrier and eczema could play a key role in triggering food sensitivity in babies, which could ultimately lead to the development of food allergies," Dr. Carsten Flohr, of King's College London, said in a college news release.
The researchers said the discovery suggests that food allergies may develop via immune cells in the skin rather than in the gut and that the findings indicate that eczema may be a potential target for preventing food allergies in children.
A link between eczema and food allergies has been known for some time, but this study -- published July 18 in the Journal of Investigative Dermatology -- adds to growing evidence of the skin barrier's role in the process, according to the researchers.
The study included more than 600 infants who were 3 months old and exclusively breast-fed from birth. They were tested for eczema and checked to see if they were sensitized to the six most common allergenic foods.
Egg white was the most common allergen, followed by cow's milk and peanuts. The more severe the eczema, the stronger the link to food sensitivity, independent of genetic factors.
It's believed that the breakdown of the skin barrier in infants with eczema leaves active immune cells found in skin exposed to environmental allergens -- in this case food proteins -- which then triggers an allergic immune response, the researchers explained.
They also noted that food sensitivity does not always lead to food allergy and they're conducting a follow-up of the infants in this study.
"This work takes what we thought we knew about eczema and food allergy and flips it on its head. We thought that food allergies are triggered from the inside out, but our work shows that in some children it could be from the outside in, via the skin," Flohr explained. "The skin barrier plays a crucial role in protecting us from allergens in our environment, and we can see here that when that barrier is compromised, especially in eczema, it seems to leave the skin's immune cells exposed to these allergens."