Researchers try to solve the mystery of food allergies

From The New York Times:

CHICAGO — For 5-year-old Sean Batson, even a grandmother’s kiss is to be feared.

“My mother was wearing lipstick, and when she kissed Sean’s cheek, it broke out in hives,” said his mother, Jennifer Batson.

At his first birthday party, Sean (pictured) had a severe allergic reaction — hives, swollen eyes, vomiting and wheezing — to his first nibble of cake. And when a toddler with an ice cream cone touched Sean’s arm with sticky hands during a play date, the arm erupted in hives.

The daily struggle of living with Sean’s allergies to nearly unavoidable foods and food products — soy, eggs and milk, traces of which can turn up even in nonfoods like lipstick — prompted Mrs. Batson and her husband, Tim, to participate in a project that scientists are calling the most comprehensive food allergy study to date.

The international study, led by Dr. Xiaobin Wang and Dr. Jacqueline A. Pongracic of Children’s Memorial Hospital here, is searching for causes of food allergy by looking at hundreds of families in Boston, Chicago and Anhui Province in China.

Using questionnaires and interviews, the investigators are gathering data on a broad range of environmental, genetic and health factors, among them diet, hygiene, number of pets and the children’s prenatal and postnatal medical histories.

Dr. Wang says the study’s multicenter design allows researchers to look at startling variations in the prevalence and types of food allergies across diverse populations and regions.

In China, for example, skin-prick testing found that large percentages of one rural population were sensitive to shellfish (16.7 percent) and peanuts (12.3 percent). Yet actual food allergies in that population, as diagnosed by physicians, were all but unheard of: less than 1 percent.

In the United States, by contrast, 12 million people (4 percent of the population) suffer from food allergies, according to the Food Allergy and Anaphylaxis Network, a nonprofit information and advocacy group.

“We found something unexpected,” said Dr. Wang, director of the Smith Child Health Research Program at Children’s Memorial. “The apparent dissociation between high allergic sensitization and low allergic disease in this Chinese population is not seen in our two U.S. study populations.

“What can explain the U.S. and China difference?” she asked. “Is it urban versus rural exposure? Diet and lifestyle? Or genetic susceptibility? These are all questions we are trying to find some clear answers for.”

For Sean Batson and his family, a recent clinical evaluation at the hospital included a skin-prick test to establish baseline data for Sean’s sister, Audrey, 1, who does not seem to have food allergies. (Neither do their parents, Tim Batson, 38, a computer programmer, and Jennifer Batson, 36, a copy editor.)

Sean was given a fresh skin-prick test, too. The mild discomfort was tempered by an episode of “SpongeBob SquarePants” playing on a minimonitor affixed to a cushy reclining chair. Dr. Wang said her own awareness of food allergies was heightened after her twin sons started kindergarten in Boston and began bringing home an abundance of notes warning of severe food allergies among their classmates.

“Going back 10 to 15 years ago, during my pediatric residency training, there was very little education about food allergies,” said Dr. Wang, one of 12 principal investigators who were recently awarded grants by the National Institutes of Health to conduct innovative research on food allergies.

Indeed, with recent data showing a marked increase in the number of food allergies, which cannot be explained by a lack of detection in years past, the institutes have begun an initiative to address food allergies as an emerging health challenge.

Although it is possible to be allergic to any food, eight foods account for 90 percent of all reactions — milk, eggs, peanuts, fish, shellfish, soy, wheat, and tree nuts like cashews and almonds.

Up to 200 deaths each year are attributed to the most severe reaction, food-induced anaphylaxis, which also results in 30,000 trips to the emergency room. Some experts suggest that children in a culture smitten with antibacterial detergents and hand sanitizers are exposed to fewer germs, depriving the immune system of its germ-fighting job and leading it to misidentify certain foods as foreign.

But that is still just a hypothesis, and many researchers say the causes of food allergies are highly complex, and the “hygiene hypothesis” cannot be the sole explanation.

Dr. Pongracic, who has been treating children with food allergies for 17 years, says even trace amounts of allergens can cause life-threatening reactions.

“Ultimately, we hope that our research will lead to the discovery of ways to predict which child is likely to outgrow food allergy,” she wrote in an e-mail message, adding that doctors hoped to develop therapies “that can lessen the severity of an allergic reaction, and even protect against the reaction in the first place.”

Frustration over the lack of financing for food allergy research led one Chicago-area couple, David and Denise Bunning, to donate $3 million to the study at Children’s Memorial. As the parents of two sons with life-threatening food allergies, they say they hope to convince lawmakers that food allergies deserve as much public attention as other chronic childhood diseases like asthma and Type 1 diabetes.

“At first I thought, ‘O.K., you have this one-in-a-million kid with severe food allergies, and you just have to cope,’ ” said Mr. Bunning, a financial trader. “But when we learned that both Bryan and Daniel had severe food allergies, there was a lot of disbelief. It felt like we were hiding from a phantom.”

Mrs. Bunning, a former teacher, added: “Now, we’re pretty excited about the future findings of the allergy study. We need to start looking at food allergies not as something you pick and choose as a parent, but as a childhood disease with potentially life-threatening reactions, even death.”