Propped on his elbows and glued to an episode of Max and Ruby, my then-3-year-old son, Henry, was oblivious to the nurse marking his back with a ballpoint pen in preparation for a lengthy skin test. We were at the allergist's office looking for answers. What was causing Henry's frequent swollen eyes and breathing problems? Could an allergen be to blame for his irritability? Like any neurotic mommy-on-a-mission, I wanted a doctor to tell me what was going on and why.
The cartoon worked at distracting Henry—until the first prick. He winced through 50 more. His back looked like a messy grid of roughly 110 tiny red splotches and rubbed-away ink. Only five bumps on Henry's back puffed slightly—identified later as egg whites, sweet potatoes, almonds, crab and dust. The doctor instructed me to restrict those foods from Henry's diet and then reintroduce them one at a time during the coming month. I was confounded—all the foods were ones Henry had eaten before without incident. It didn't feel right to me, and my maternal instinct pushed me into learning all I could. The experience welcomed me to the dizzying world of food-allergy diagnosing.
Margin of Error
More than 3 million American kids have food allergies, according to the Centers for Disease Control and Prevention. It's a number that is growing rapidly—up 18 percent between 1997 and 2007. More children are being diagnosed with life-threatening food allergies than ever before. Some outgrow them. Some don't. While many doctors agree that the number of legitimate food-allergy cases is rising, many also believe the numbers may be inflated because of heightened awareness and a heavy reliance on tests that aren't 100 percent accurate. As a result, thousands of children may be misdiagnosed, and families may be unnecessarily restricting their kids' diets.
"Diagnosing food allergies is a very uncertain science," said Rauol Wolf, M.D., professor of pediatrics and director of pediatric allergy and immunology at the University of Chicago's Comer Children's Hospital. "Is it really increasing, or are people more aware and we're overdiagnosing? The answer is yes and yes."
Skin tests, such as the one given to my son, have an estimated 40 percent to 70 percent false-positive rate, meaning that the patient can have a positive result but not have any reaction after eating the food, Dr. Wolf says. That raises questions about accuracy. Children also can outgrow food allergies but still display positive reactions on a skin test. In addition, medications such as antihistamines can interfere with results. For parents hoping for clear-cut answers, skin tests are only reliable when no allergic reaction presents. "False positives are common, but false negatives are not," Dr. Wolf explains.
As an alternative to skin tests, doctors may order blood tests; however, these carry the same limitations as do skin tests. Blood testing measures a sample of blood for levels of allergy-inducing antibodies (IgE) to foods or substances, which would indicate an allergic reaction is possible. However, the antibodies alone don't cause allergic reactions, says Dr. Wolf. "Everybody can have IgE to foods, and not have a reaction when they eat them—that's why we have false positives." Blood tests merely identify the presence of IgE. Blood tests also can't distinguish between similar proteins. For instance, a child with a dairy allergy may receive high antibody levels to beef as well, without actually being allergic. A positive test correlates with real reactions less than half the time, according to the most recent research in Pediatrics, the American Academy of Pediatrics (AAP) journal.
Because of the room for error and discrepancies, medical researchers are calling for stricter food-allergy diagnosing guidelines, as evidenced in a recent article in the Journal of the American Medical Association. It's a sentiment that many anxious parents echo—including those who may be restricting their children's diets unnecessarily—and a hot topic on online message boards, where worried parents flock for information and support. "There is so much misinformation, ignorance and insensitivity concerning food allergies," one mom wrote on the Facebook page for Kids With Food Allergies, a Pennsylvania-based nonprofit group. "More research needs to be done, and scientists need to generate alternate theories and actually test them," wrote another.
The key to wading through the world of food allergies is for parents to arm themselves—and their allergists—with as much information as possible, says Lynda Mitchell, president of Kids With Food Allergies. Dr. Wolf agrees: "Diagnosing a food allergy is easier when parents provide a comprehensive family history, food diaries and a complete list of symptoms." After all, parents are on the frontline. They've seen the symptoms firsthand, and they know whether their child has or hasn't tolerated certain foods in the past. "The bottom line is, don't base a diagnosis on test results alone," Mitchell says.
It took dozens of doctors and tests to properly diagnose Sara and Daniel Atkins' four children. This went on for years, especially for 6-year-old Tevye and 4-year-old Freida, who both have asthma. Local doctors were befuddled and put the kids on highly restrictive diets, leaving only a handful of foods. Even then, conditions worsened. Freida, a toddler at the time, stopped gaining weight and began losing her hair. "They weren't getting better," Sara says. "But nobody was listening to us."
Desperate for answers, the Atkins enlisted the help of a team of allergists in Denver, more than a thousand miles away from their home in Wynnewood, Pennsylvania, and spent weeks there reviewing their children's symptoms and performing tests. "We learned that Tevye and Freida's immune systems were so compromised (from eczema) that they were reacting to anything and everything," Sara says. Along with brothers Zusil, 7, and Moshe, 1, both kids participated in more than 80 oral food challenges combined. "They passed almost everything they tried," Sara says. "It was wonderful, but frustrating too. Tevye avoided wheat for three years unnecessarily. Had we stayed with the original diagnosis, we'd still be avoiding more than 90 foods that are perfectly safe."
None of this is to say that food allergies aren't real; the Atkins children still experience severe reactions to foods—just like thousands of children across America. Sarah Harris' son is one of them. The Moseley, Virginia, stay-at-home mother of two boys had no idea why her oldest child, Evan, screamed in inconsolable misery for months shortly after he was born. His pediatrician told her it was colic. But at 9 months old, after three bites of baby yogurt, Evan developed a large red rash around his mouth. On her doctor's advice, Harris waited a couple of days and then fed Evan yogurt again. The lower half of his face became red. Subsequent skin tests showed that Evan had allergies to milk, eggs, wheat, oats, barley, cantaloupe, peanuts, tree nuts, shellfish and other fish. The Harris' altered their lifestyle and removed the allergenic foods from Evan's diet. His skin and comfort level improved immediately. "Talk about mommy guilt," she says. Now age 3 and starting preschool, Evan has successfully reintroduced wheat and eggs into his diet after completing oral food challenges. He also eats oats regularly without incident, but other foods still remain off-limits
Evan's symptoms—colic, eczema and reflux—are common allergic reactions. Others may include itchy or red skin, hives or rashes, coughing, wheezing, difficulty breathing, asthma or asthma-like symptoms, swelling, vomiting, nausea, diarrhea, bloody stools and more. "Infant allergy symptoms can mimic other diseases," Mitchell says. Those may include food intolerance, lactose deficiency, ulcers, gastrointestinal illnesses, even the common cold. "It's very important that parents talk to their pediatrician and visit with an allergist if they have concerns." Evan, for example, had many symptoms, "but nobody helped us connect the dots. Nobody even mentioned allergies as a possibility," says Harris. Typically, a child will experience an allergic reaction within 30 minutes of exposure. The more delayed the reaction, the less likely the child is allergic to the food, says Todd Green, M.D., an allergist/immunologist at Children's Hospital of Pittsburgh of UPMC. If a parent suspects a milk allergy, but the symptoms don't show up until several hours later, something else may be to blame.
Researchers are actively working on treatments for children who may never outgrow their food allergies, a number that depends on the allergen. Eighty percent of kids with a milk allergy will outgrow it, but only 20 percent of those allergic to peanuts will. Immunotherapy studies that gradually give children increasing amounts of the allergic substance in order to teach the immune system to tolerate it have already showed encouraging results, says Robert A. Wood, M.D., professor of pediatrics and director of allergy and immunology at Johns Hopkins Hospital in Baltimore. Dr. Wood has successfully cured milk allergies for more than a dozen children. Some can now ingest unlimited quantities of milk or dairy products, while others can tolerate it in measured amounts. These are children who would have an allergic reaction after ingesting less than one-quarter teaspoon of milk before participating in the studies. Similar egg and peanut studies are under way. "It's really life-changing," Dr. Wood says. "These are children who were at severe risk if they ate even one bite of birthday cake. Now, many of them can have cake and ice cream."
What can parents do?
Doctors used to recommend that parents wait at least until age 1 to feed potentially high-allergenic foods to children. In 2008, the American Academy of Pediatrics released new guidelines stating that there isn't enough evidence to support the theory that dietary restrictions play a significant role in preventing food allergies. Some researchers, like Dr. Wood, believe that introducing high-risk foods early may actually boost a child's tolerance for allergenic foods. They look to counties like Thailand, where peanuts are part of the daily cuisine, yet peanut allergies are very rare.
Breastfeeding is one way moms can help fend off potential food allergies. The AAP reports that nursing for at least four months, compared with feeding formula made with cow-milk protein, prevents or delays the occurrence of allergies in early childhood. It's also a wise idea to introduce new foods gradually after the child is 4 to 6 months old. The AAP recommends waiting several days after each new menu item to make sure there isn't a reaction. Parents who think their children may have food allergies (if allergies run in the family, for instance) should talk with their doctor to determine the best strategy for introducing foods, says Mitchell.
Finding a cure isn't something that Stephanie Heath of Overland Park, Kansas, thinks about much as she prepares special sack lunches or teaches her two severely allergic kids to read food labels. But she is quick to count her blessings. "At the end of the day, my kids are healthy and happy, and we can manage the allergies," she says. "We're blessed." As for my son, Henry, my maternal instinct was right on target. We eliminated the suspect foods for a month and then purposely added each one, waiting a few days in between. He may not like sweet potatoes, but there's certainly not a medical reason why he should avoid them.