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Recognizing and coping with childhood food allergies

I've heard that more and more children are developing potentially dangerous food allergies. Is this true, and if so, how do I know if my child is allergic to certain foods?

The prevalence of allergies worldwide has been increasing in recent years, but according to Boris Balson, a MED assistant clinical professor of pediatrics, the uptick in food allergies among children is probably a sign of better detection and diagnosis by parents and physicians. “The number of pediatric patients with food allergies is certainly growing,” he says, “and I think the rise has been multifactorial: there are now better diagnostics, and moms are also more aware of the possibilities of food allergies. Food allergies have always been much more prevalent in kids than in adults. About 4 to 7 percent of kids suffer from some kind of food allergy.”

The spectrum of common food allergies varies depending on the age of the patient, Balson says. “In small kids, the most common allergies are to cow's milk, eggs, wheat, soy, and in some cases, nuts,” he says. “After about 12 years of age, nut allergies become much more prevalent, as well as seafood and dairy allergies.

“There are some food allergies that are exceptionally dangerous for the patient, and some that are not. The most dangerous ones are to nuts, because these patients are very prone to anaphylactic reactions, which involve life-threatening symptoms like severe problems with breathing, and cardiovascular problems.” While some people may believe that kids who are allergic to peanuts can go into anaphylactic shock by just sitting next to a friend who's eating a peanut butter and jelly sandwich, Balson says such incidences are not very common. “Usually, we're talking about firsthand intake of nuts.”

Food allergies are fairly easy to recognize in infants, he says. “The signs of allergies in infants include skin rashes, diarrhea, flatulence, abdominal colic, and swelling. Parents might notice their kids' arms or face swelling after eating a certain kind of food. There's one universal approach to treating these allergies: avoidance. It's of paramount importance to find out which food is causing the allergic reaction. Unfortunately, unlike a lot of environmental allergens, which can be treated with allergy shots, there is not any immunotherapy that's been developed for food allergies.”

Pediatricians usually diagnose allergies with the food skin test, which involves scratching the skin and applying a special serum with the suspect food allergen, such as cow's milk or nuts. “We can test up to 50 or 60 different allergens and read the results in 20 minutes,” Balson says. “It's fast and painless, but it does have some limitations. It doesn't work when the patients are taking antihistamine medications or if the patients have severe skin problems. If we can't do the skin test, we can do a RAST test, which involves taking a blood sample and analyzing it for its specific IgE antibodies to these food agents. This is less sensitive and less reliable.”

Balson encourages parents to consult a pediatrician about possible food allergies in their kids. He's also adamant about being prepared for the worst: “Every patient with a food allergy has to have an EpiPen available at all times,” he says. Devices like the EpiPen administer a dose of epinephrine, which helps counteract anaphylaxis in emergencies. “It's very easy to use, it doesn't require any special skills or medical knowledge, but it will save your life in the event of a severe allergic reaction.”

20 February 2004
Boston University
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