Children most at risk for hidden food allergies

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AllergyMILWAUKEE - When Colleen Pfaff was a toddler, her father forgot to wash his hands after handling blue cheese for a salad, and lifted Colleen into the tub to give her a bath.

Hand-shaped welts immediately appeared on Colleen’s body. Her immune system had reacted to milk protein still on his hands.

The welts subsided after washing with soap and water. But it was a painful lesson in how little it can take to trigger an allergic reaction to food.

‘‘My brother-in-law is a doctor,’’ said Colleen’s mother, Jane Pfaff of Wauwatosa, Wis. ‘‘He said if he hadn’t been there that night and seen the welts himself, he never would have believed it.’’

For a large number of Americans with food allergies, meals and snacks are a minefield of allergens - some easy to spot; others not.

Food allergies are taking on a higher profile with efforts to educate the public about their serious risks and with new food labeling laws designed to make allergens easier to detect.

Many schools are developing plans to keep kids with food allergies safe.

Those with severe allergies may appear healthy. But their health depends on avoiding foods that make them ill, as there is no known cure. They constantly read food labels for hidden ingredients and question how food was prepared, in case it somehow touched other food that could harm them.

Cross-contamination can happen as easily as using the same spatula to flip eggs, prepared for a non-allergic person, to also flip pancakes for someone allergic to eggs.

Food allergies appear to be on the rise, though they weren’t methodically tracked until recent years, said Scott Sicherer, associate professor of pediatrics and a researcher for the Jaffe Food Allergy Institute at Mount Sinai School of Medicine in New York.

‘‘It seems in the past decade, we have seen a significant rise in all types of allergic disease, such as asthma, hay fever and food allergies,’’ he said. ‘‘If you go into most schools and ask a school nurse how many children have food allergies, they will anecdotally say there’s more.’’

The severity of reactions varies widely, from hives and rashes to severe swelling in the throat and a rapid drop in blood pressure, a pattern known as anaphylaxis. Some develop mainly gastrointestinal symptoms, such as nausea and vomiting.

Sensitivity to allergens also varies. Some must eat a modest amount of food to have a reaction, while others may react from even trace amounts.

Researchers don’t know why allergies appear to be on the rise. Genetics play a role, but they don’t entirely explain it.

The ‘‘hygiene theory’’ has emerged as one plausible explanation, Sicherer said.

Researchers who advocate this theory speculate that in modern, industrialized nations, such as the United States, food allergies are more common because of reduced exposure to germs.

Overuse of antibiotics and anti-bacterial cleansers, and increased use of vaccines to protect from illness, may be partly responsible, they say.

Studies indicate that allergies are less common in Third World countries and among those who live on farms.

With fewer germs to fight off, the body turns on itself and attacks food proteins as if they were foreign invaders, the hygiene theory suggests.

‘‘We’re not challenging our immune system, so it attacks something it doesn’t need to attack - protein in food,’’ Sicherer said.

Another theory is that infants are being exposed to some foods too early, before their digestive systems are developed enough to break down that protein and process it, Sicherer said.

A food allergy is caused by the body’s immune system mistaking an ingredient in food - the protein - as harmful and creating a defense system (antibodies) to fight it. An allergic reaction occurs when the antibodies battle an ‘‘invading’’ food protein.

Allergies abound

Nearly 12 million people - roughly 1 in 25 Americans - are believed to be affected by one or more food allergies, according to The Food Allergy & Anaphylaxis Network.

The network is a nonprofit organization established to raise public awareness about food allergies and anaphylaxis, and to advance research.

Food allergies among young children are especially challenging, as children depend on adults in day-care centers, schools and other settings to be educated about the nuances and dangers of food allergies until they are old enough to take responsibility for themselves.

Nineteen-year-old Marcus Davila, a promising young Milwaukee actor with a severe peanut allergy and asthma, died three years ago. He apparently had a severe reaction to peanuts, possibly to Chinese food cooked in peanut oil, and died soon after arriving at a hospital emergency room.

Deaths are rare, but emergency room visits are not.

Food allergy-related deaths number 150 to 200 a year in the United States, but as many as 30,000 visits to the emergency room each year are attributed to allergic reactions to food. Most ate food they thought was safe.

Peanuts, for example, may be hard to detect in foods. Some schools have been declared ‘‘peanut-free’’ because of the presence of students with allergies.

Other schools grappling with the safety of those with food allergies provide allergen-free tables in cafeterias.

Schools may restrict treats brought from home and work to eliminate hidden allergens, such as finger paint containing egg whites, art projects involving tree nuts and math exercises involving candy containing peanuts.

One study suggests that the number of children diagnosed with peanut allergies doubled between 1997 and 2002, to nearly 1 percent of those younger than 18, or about 1 in 125 children, said Sicherer, the allergist.

Peanuts are the leading cause of allergic reactions and are associated with the most severe reactions, according to The Food Allergy & Anaphylaxis Network.

Two-thirds of deaths from food allergies are connected to peanuts, said Lauren Charous, a Milwaukee allergist who runs a chronic cough and sinus center for Advanced Healthcare.

‘‘Why do allergens differ in potency? I don’t know,’’ Charous said.

Milwaukee Public Schools has a new computer system that alerts food service workers when students with food allergies are in the cafeteria line.

Students punch personal identification numbers into a lunch-line machine.

For those with food allergies on record at the school, their pictures pop up along with notations flagging their specific allergies so cafeteria workers know to offer alternative foods.

An MPS staff dietitian also works with school nurses, teachers and families of children with food allergies to develop plans to protect the child and quickly respond to an allergic reaction, said Kymm Mutch, director of school nutrition for MPS.

School bans on certain foods, such as peanuts, are not without controversy.

‘‘Where do you stop? Do you eventually ban all food from school because someone is allergic to it?” asked Kyla Lahaie, a parent who is allergic to iodine. ‘‘It’s a parent’s responsibility to care for their own child and teach that child to be responsible for him- or herself. The teacher should know how to respond to an emergency, but where do you draw the line when you go down the path of banning foods?”

Many children outgrow food allergies by the time they become teens, but others do not. Some food allergies get worse over a lifetime.

A person could have an allergy to almost any food, but eight foods account for almost 90 percent of allergic reactions: milk, eggs, peanuts, tree nuts (such as cashews and walnuts), fish, shellfish, soy and wheat.

Teens are the highest risk group for fatal induced anaphylaxis because of how they respond to perceived risks and social pressures, according to a study published in the June issue of the Journal of Allergy and Clinical Immunology.

Only 61 percent of teens involved in that study said they always carried their epinephrine, a life-saving medication used during anaphylactic episodes, and the carrying rates varied by activities or circumstances such as traveling (94 percent), participating in sports activities (43 percent), wearing tight clothing (53 percent) or attending school dances (61 percent).

Researchers are striving to develop therapies to treat and prevent food allergies.

A new Food Allergy Research Consortium, led by one of Sicherer’s colleagues at the Mount Sinai School of Medicine, is doing a clinical study to evaluate a potential peanut allergy therapy.

Sicherer recently studied how long peanut butter may linger in the mouth to assess the risk of passionate kissing between a partner with a peanut allergy and one without.

‘‘Our conclusion was that usually waiting a few hours and then eating a meal that has no peanut should result in no appreciable residual peanut,’’ Sicherer said. ‘‘But the safest advice for a partner would be to avoid the food their partner is allergic to.’’

A grass-roots effort over the past decade led Congress to approve a food labeling law in 2004, which ultimately won the support of industry trade groups. The new law, which went into effect in January, raises the liability of food manufacturers who fail to identify the top eight allergens in packaged product labeling.

If a product is derived from or contains an ingredient with protein from any of the eight major allergen categories, the label must disclose it in plain English.

The requirements do not apply to major food allergens that are unintentionally added as the result of cross-contact, according to the U.S. Food and Drug Administration.

Cross-contact may result from growing and harvesting crops, the use of shared storage, transportation or production equipment. Manufacturers are free to include ‘‘may contain,’’ ‘‘processed on equipment used for’’ or other advisories at their discretion.

Common food allergens The following foods account for 90 percent of all food allergies:

* Eggs
* Fish
* Milk
* Peanuts
* Shellfish
* Soy
* Tree nuts
* Wheat

Labeling law In 2004, Congress passed food-labeling legislation requiring manufacturers to disclose in plain English the presence of the eight most common food allergens. It went into effect in January. The law also calls for inspections of processing facilities regarding cross-contamination and coordination of research into food allergies.

By the numbers

About 12 million Americans have diagnosed food allergies, with an estimated 6.9 million allergic to seafood and 3.3 million allergic to peanuts or tree nuts.

Roughly 5 percent of children and 2 percent of adults have allergies.

One in every 17 children younger than 3 has a food allergy. An estimated 80 percent to 85 percent outgrow the allergy by age 3. Nevertheless, some 2.2 million school-aged children still have food allergies.

Eight foods account for 90 percent of severe allergies: peanuts, tree nuts, fish, shellfish, eggs, milk, soy and wheat.

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