When And How Do You Perform Food Challenges?

— -- Question: When and how do you perform food challenges?

Answer: Food challenges are done for two different reasons. One is to confirm that a child likely has outgrown that food allergy. We know that milk, egg, wheat and soy allergies typically are outgrown by school age. And so, to find that out -- the child may still have IgE to milk, but they're likely, because of small amount of IgE that's there, that they're not allergic. So you would do a food challenge, giving them -- under the supervision of a physician -- small amounts, increasingly that amount over about an hour, to find out if they're going to react. And if they can tolerate, you know, say, a glass of milk, then they're no longer allergic to that food.

The other reason that food challenges are done is to try to find out if a child or an adult is allergic to that particular food. Their history is somewhat convincive, but their IgE tests aren't diagnostic, so then a food challenge would say, "Yes, you're allergic to the food," or "No, you're not allergic to it."

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