Pinpointing and managing food allergies can seem overwhelming, because food allergies can range from mildly inconvenient to truly terrifying, particularly for parents of children who have food allergies.
“When we say ‘food allergy,’ we’re typically talking about immediate, potentially life-threatening, reactions,” says Dr. Jeremy Bufford, an allergist and immunologist with the Meriter Medical Group. “It can be hard to find the trigger, especially if you are eating several foods at once, but these episodes are usually not subtle.”
The foods that most commonly cause allergic reactions in people are eggs, milk, soy, wheat, peanuts, tree nuts, fish and shellfish. Children who are allergic to certain foods, such as eggs, dairy, wheat and soy, typically start to develop allergies early in childhood and often outgrow those allergies by the age of nine or ten.
“The prevalence of food allergies is definitely on the rise over the past ten to twenty years, especially in children,” says Bufford.
If you suspect an allergy, call an allergy specialist for an appointment. In combination with a detailed history, allergy testing is performed using a skin-prick test, a blood test, a food challenge, or a combination of all three. Food allergy testing is not a perfect science; fifty percent of the time, skin tests and blood tests produce false positive results. Allergists work closely with patients to customize testing so that no unnecessary risks are taken, with the goal of keeping as much food in the diet as possible.
“As allergists, we never want someone to avoid a food they don’t have to,” says Meriter allergist and immunologist Dr. Katherine Gonzaga. “Some people think a food is guilty until proven otherwise, but we often take a different approach unless the trigger is rather obvious.”
To develop an allergy to a particular food, patients must have been exposed to it—in utero, through breast milk, through environmental exposure, or simply by eating it. Food allergies can develop suddenly, even if the patient has previously tolerated the offending food. Some can also disappear, so allergists will monitor blood levels and skin-test results over time. About twenty-five percent of kids grow out of egg allergies, for example, by the time they are six years old. Fifty percent will do so by age ten and eighty percent by age sixteen. Unfortunately, only twenty percent of people who develop a peanut allergy in childhood will outgrow it, and only about ten percent will outgrow a nut allergy. Fish and shellfish allergies tend to last for life as well.
“They don’t just come and go,” says Bufford, of these types of food allergies. “Reactions usually occur consistently with each exposure, and the severity may actually worsen over time.”
Adding to the mystery of managing a food allergy is the problem of “cross-reactivity.” This is where the immune system confuses one allergen with another, and reacts. For instance, some patients sensitized to pollen will have a reaction when they eat certain raw fruits or vegetables. Wheat is cross-reactive with grass pollen, for example, and melon is cross-reactive with ragweed pollen. Raw apples, peaches, pears and cherries are all intensely cross-reactive with birch tree pollen. Peanuts and soy
After testing and diagnosis, Bufford and Gonzaga help their patients develop a Food Allergy Action Plan to try to prevent or manage exposure through cross-contamination or accidental ingestion.
“We help make sure caretakers—schools, daycares, nurseries—know about the food allergens, food restrictions, and are prepared to treat a potential immediate reaction,” says Gonzaga.
There is no cure for food allergies but new research is moving toward “desensitization,” which is the same idea behind allergy shots given for environmental allergens. The goal is to help patients develop a clinical tolerance of an allergen through regular exposure to it.
“The research is very promising,” says Bufford. “The hope is that we’ll come up with some commercially available product to cure food allergies. That’s the goal, and I think we’re closer now than we’ve ever been.”