One of the first things parents ask when their child is diagnosed with food allergy is, “When will he outgrow it?” That’s because it’s been conventional wisdom that most children outgrow food allergies – particularly milk and egg – within a few years. Today, however, research shows that food allergies persist into childhood longer.
Two studies highlighted in the Journal of Allergy and Clinical Immunology (November and December 2007) followed the progress of more than 800 children with milk allergy and almost 900 children with egg allergy over 13 years. The results showed a major shift in how these allergies progressed in children. Early research suggested that 3 out of 4 children would outgrow milk allergy by age 3. In the new studies, only 1 out of 5 children outgrew milk allergy by age 4, and less than half the children had outgrown it by age 8. By age 16, almost 80 percent of the children were free of milk allergy. Egg allergy followed similar trends.
What’s causing this shift in allergy rates? “The ‘why’ is still an unanswered question,” says Robert Wood, MD, lead investigator of the studies and one of the foremost U.S. experts on food allergies. “I am definitely seeing this in my practice, which is why we did the studies. I suspect that the same factors that have led to the increase in food allergies are also related to the greater persistence. I believe that food allergy is a different disease than it was 20 or 30 years ago.”
The important question for parents is what they should do about it. The answer: Monitor your child’s diet carefully and work with an allergist for accurate diagnosis and a management plan.
Dr. Wood says he tracks his patients’ allergies with blood tests at least once a year. Blood tests measure the amount of allergy-specific IgE antibodies (a sign of allergy) in a patient’s blood – the higher the milk IgE count, for instance, the more likely the patient is to be allergic to milk. If the IgE count begins to decrease, it may mean the patient will eventually be able to drink milk without an allergic reaction. It’s important to work with a board-certified allergist specializing in food allergies, who is trained to interpret these numbers accurately and should be up-to-date on the most recent research in the field.
If blood tests indicate your child’s allergy may be going away, your allergist is likely to recommend a food challenge (a.k.a., taste test done at the doctor’s office) to see whether your child is able to consume the food without an allergic reaction.
If all goes well during the food challenge, Dr. Wood recommends parents gradually add more and more of the food to the child’s diet. “It’s important to follow the doctor’s instructions carefully and proceed slowly,” he writes in his book, Food Allergies for Dummies®. “Once you can tolerate a full serving of the food over a period of several days, your doctor is likely to lift all restrictions, so you can consume all forms of the food.”
Dr. Wood advises parents to be watchful for signs of allergy, even after it seems to have gone away. Recurrences of milk and egg allergy are rare, he says, but peanut allergy is known to return.
There’s so much we don’t know about food allergies. Research is adding to our understanding every day, but we have a long way to go. That’s why it’s important to work closely with a specialist, follow instructions carefully and listen to what your body tells you.
First published: Allergy & Asthma Today, Volume 6, Issue 1
Updated: February 2009