The number of children suffering from food allergies in the United States is estimated to be as high as eight percent, and, between the years 1997 and 2007, the prevalence of food allergies increased a full 18 percent. A new animal study, which investigated the development of food allergies, suggests proteins in food may be responsible for causing inflamed skin, and so an overall link exists between skin sensitization, gastrointestinal inflammation, and food reactions.

A food allergy occurs whenever the body has an unusual immune response to specific foods. Essentially, the immune system, which normally protects your body against harmful germs, responds to food as if it were a toxic pathogen, a virus, say, or poison. Eight foods or food groups account for 90 percent of all serious food reactions in the United States: milk, eggs, fish, crustacean shellfish, wheat, soy, peanuts, and tree nuts. At times, the body’s immune response is so severe it becomes life threatening, as in the case of anaphylaxis. Unfortunately, because allergies may be life threatening and have no cure, they impact not only the sufferer’s life but also that of their families and schools. After all, a child is a child and might easily eat something dangerous, especially if it looks like candy.

To explore food allergies more closely, Dr. Steven Ziegler and his colleagues at the Benaroya Research Institute developed a mouse model for a series of experiments. After a number of trials, they discovered that exposing the skin of mice to a combination of a food antigen (peanut or egg proteins) and a pro-inflammatory molecule known as thymic stromal lymphopoietin (or TSLP), which exists in both humans and mice, would result in a food allergy. In fact, a simple dermal application of TSLP resulted in a severe allergic reaction, including diarrhea and anaphylaxis, whenever the mice ingested the antigen at the same time. Experimenting further, the researchers found skin sensitization to the antigen required TSLP. They also discovered mice lacking in receptors for IL-25, a protein that regulates intestinal response, did not develop a reaction.

“These results demonstrate a role for TSLP and IL-25 in the atopic march from skin sensitization to food allergic responses and provide a model system for the generation of potential therapeutic interventions,” wrote the researchers in their published study. In plain speak, this work could lead to more accurate methods for testing drugs to either cure, treat, or prevent food allergies in children.

Source: Han H, Thelen TD, Comeau MR, Ziegler SF. Thymic stromal lymphopoietin-mediated epicutaneous inflammation promotes acute diarrhea and anaphylaxis. Journal of Clinical Investigation. 2014.