What makes a food allergy?

By Michaela Gibson Morris/NEMS Daily Journal

Allergies cover a lot of ground.
Pollen, weeds, mold, insect stings, medication, fumes and foods are just the top of the list.
They all involve some overreaction of the immune system to something that should be innocuous. The reactions range from occasionally annoying to life-threatening.
In people with IgE-mediated food allergies, a specific piece of the immune system – Mast cells – become hypersensitived to IgE antibodies specific to a protein from a food, said Tupelo Allergist Dr. Matt Oswalt. The most common foods to trigger these allergies are peanuts, tree nuts, fish, shellfish, milk, soy, eggs and wheat, but people can sensitive to a number of different foods and they can be allergic to multiple foods.
After an initial exposure, the mast cell is primed to cause a systemic set of reactions when that protein arrives again, including hives, vomiting, diarrhea, low blood pressure and difficulty breathing. In severe cases, the whole body reaction – called anaphylaxis – can be life-threatening.
“Some kids have problems with the first reported exposure,” Oswalt said. “Most have an exposure first and then have an episode on the second.”
People who have a history of these severe reactions are usually prescribed epi-pens, to give them medication to buy time to seek medical treatment.
There are other conditions that involve the immune system and food.
Celiac disease, for example, is the result of an inflammatory response that causes a hyper sensitivity to gluten.
Many people have food intolerances, like lactose intolerance, where their bodies are missing an enzyme that makes it difficult for them to digest those foods.
However, these conditions do not cause the system-wide anaphylactic reactions, Oswalt said.

Allergy emergency
• If a child is wheezing and breaking out in hives after eating or drinking, they are likely having an anaphylactic reaction to a food. Parents should call 911, said Tupelo Allergist Dr. Matt Oswalt.
• FACE IT Tupelo – a support group for parents of children with food allergies, meets twice a month on the first Friday and third Monday. The group is also open to those with conditions that require food avoidance. Affiliated with the Food Allergy and Anaphylaxis Network. Contact Amelia at (662) 322-7434 or faceittupelo@live.com for time and place. Next meeting will be noon, Aug. 5, at the Gloster Creek Village Food Court.
• Food Allergy and Anaphylaxis Network – www.foodallergy.org: National organization offers information on food allergies, advocacy and research.

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