Allergies: Widespread Reactions

When Koby Tavel was 10 months old, his father fed him a spoonful of salmon. His skin promptly puffed up. Cursed with allergies in his first years, Koby often erupted in hives and eczema. His lips swelled after they brushed a peanut butter sandwich, and a half-eaten cup of Jell-O landed him in the hospital. "It was really traumatic," his mother, Aviva Tavel, says.

After painful trials and errors, Tavel discovered that Koby, now 4, was allergic to dairy, eggs, fish, peanuts, tree nuts, melons, sesame and strawberries. "Sometimes I feel really alone," she says. "There are so many things we can't do with him because we have to control his environment."

Tavel is not as alone as she feels: Between 6 million and 7 million Americans suffer from food allergies, and they represent a growing group, says Robert Wood, a pediatrician and allergy expert at Johns Hopkins Children's Center in Baltimore. "It's similar to the increase in all the allergic diseases, including asthma, that we have seen in the last 15 to 20 years."

In particular, the number of people with peanut allergies has grown. These reactions are responsible for about 100 deaths per year and one-half of all emergency room visits caused by food allergies. A study found that the number of peanut-allergic kids doubled between 1997 and 2002.

Unlike the U.S. and other Western nations, the world's less developed countries have not become allergy-ridden. The contrast has sparked the "hygiene" hypothesis: The fewer germs an immune system is exposed to, the more likely it is to create antibodies to fight substances that are not in fact harmful. These antibodies can cause allergic reactions.

This is not an excuse to keep a dirty house, but the theory has led to experiments in which pregnant women are given probiotics, or friendly bacteria, found naturally in the intestinal tract, to occupy their babies' immune systems. "We are optimistic that in 10 to 15 years there will be ways to play with the immune system that may tip it away from developing allergies," says Wood.

TNX-901, a drug that works to prevent peanut reactions by fighting peanut-sensitive antibodies, has tested very well in preliminary trials and is expected to be available to the public within a few years.

Greater awareness of food allergies is partly responsible for the increase in diagnoses, says Anne Munoz-Furlong, director of the advocacy group Food Allergy and Anaphylactic Network. "Also, our diet has changed. We are eating peanuts more, and at an earlier age," she says. The American Academy of Pediatrics recommends that in families where at least one parent is allergic, kids should not have peanut products before age 3, eggs before age 2, or cow's milk before age 1.

Some toddlers shed their allergies along with their blankies. Wood found that 20 percent of children under the age of 4 do outgrow their peanut allergies, but if they have not it is unlikely that they ever will. The reason isn't understood but may be genetic.

In the meantime, strict avoidance of dangerous foods is the only way to manage allergies, and that is more difficult than it seems. Koby once got sick from the marinara sauce in a restaurant, says Tavel. "It turns out they cut the shrimp and then used the same knife to cut the tomatoes."