Food Allergy from the Outside In

Babies with eczema were six times more likely to have certain food allergies

(RxWiki News) Kids with eczema often itch. Eczema has also been linked to food allergies for some time. New research adds some insight into how this connection happens.A recent study found babies with eczema were more likely to have some kind of food allergy than infants without the skin condition.

The findings of this study suggest that certain immune cells in the skin might play a crucial role in how food allergies develop, according to the researchers.

"See an allergist to find out if your child is sensitive to certain foods."

This study, led by Carsten Flohr, MD, PhD, clinician scientist and senior lecturer at the St. John’s Institute of Dermatology and the Guy’s and St Thomas’ Hospital NHS Foundation Trust in London, aimed to see how certain components of eczema, or atopic dermatitis (AD), could trigger food allergies in babies.

The investigators looked specifically at how inflammation and the breakdown of the skin that occurs with eczema affects food allergy development. Eczema is the most common skin condition among children in developed countries.

The researchers looked at 619 infants who were breastfed since birth and recruited at 3 months of age. The babies were part of the Enquiring About Tolerance (EAT) study between October 2009 and April 2012.

The researchers tracked the type and severity of each child's condition. The two types of eczema were non-flexural and flexural, which is under the arms, in the groin, around the anus or under the breasts in girls.

Because eczema can dry out the skin, the amount of water lost from the babies' skin was also measured. The researchers took these measurements on the babies' unaffected forearms.

Using skin prick tests, the researchers tested children's reactions to several different food products, including peanuts, eggs, cow's milk, wheat, cod and sesame.

Babies who had eczema were more than six times as likely to have a food allergy as babies who did not have the skin condition, the researchers found. And children who had a food allergy were almost four times as likely to have eczema.

Food allergies were likely to occur in these children whether or not they lost water through the skin and regardless of the kind of eczema they had.

The researchers also found a link between eczema and the level of sensitivity to specific foods.

Babies with eczema were about nine and a half times as likely to be allergic to eggs, nine times as likely to be allergic to milk and four times as likely to be allergic to peanuts.

According to the researchers, the skin barrier plays a crucial role in protecting people from allergens in the environment. When the barrier gets compromised, the skin's immune cells are exposed to the allergens.

"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," Dr. Flohr said in a press statement.

"For years we have been in search of determining the association between AD and food allergies.  Certainly from an epidemiological perspective there is tight association; however, which comes first is of great importance in attempt to prevent disease progression.  One thing to remember regarding this study, is that skin tests or in-vitro tests alone (without an associated history of food induced symptoms) has a very high false positive response and thus a positive skin test alone does not equal true food allergy without an accompanying strong history or challenge," John Oppenheimer, MD, a physician at Pulmonary & Allergy Associates, told dailyRx News.

This study, funded by UK Food Standards Agency and the Medical Research Council (MRC), was published online July 18 in the Journal of Investigative Dermatology.

No conflicts of interest were reported.

Review Date: 
July 21, 2013