WEDNESDAY, Nov. 6, 2002 (HealthDayNews) -- Peanut allergies that seem to disappear in young children can return years later in some, raising concerns that the same may hold true for other food irritants.
An estimated one in 150 Americans are allergic to peanuts, some so acutely that even the most minimal contact with peanut proteins can trigger severe and possibly fatal reactions. Yet doctors recently have learned that as many as 20 percent of kids allergic to the peanuts as toddlers grow tolerant to them by the time they enter school -- and it has been assumed that once the allergy resolves, it never returns.
However, immune system specialists at Mount Sinai School of Medicine in New York City have found three children in whom peanut allergies gone underground resurfaced. All of the patients were boys and ranged in age from 6 to 10 when their allergy returned. Each had first suffered reactions to peanuts when they were between 1 and 1.5 years old.
"No one had ever reported that anyone who outgrew an allergy grew back into it again," says Dr. Scott Sicherer, a pediatrician at Mount Sinai's Jaffe Food Allergy Institute who saw the patients. "The remarkable thing was they not only had symptoms but they developed increased sensitization," or blood signs of sensitivity to peanut proteins.
Sicherer and his colleagues report the cases in a research letter in tomorrow's issue of The New England Journal of Medicine.
The boys were among 44 children participating in a program to chart the course of peanut allergies. Their reactions followed by about a year a doctor-monitored "challenge" with small amounts of peanut foods to see how well they tolerated them. Those, including the three boys, who didn't react to the foods were told they could safely eat peanuts at home.
Sicherer says allergists should be cautious about advising their patients with dormant peanut allergies to dive headfirst into peanut-rich foods. The rebound phenomenon probably doesn't apply with other foods frequently implicated in allergies, such as milk, eggs, wheat and soy, he says. Whether it's a factor with former allergies to fish and tree nuts isn't clear.
Anne Munoz-Furlong, founder and chief executive officer of the Food Allergy and Anaphylaxis Network, calls the latest discovery "surprising."
"What it reminds us is that when we're talking about peanut allergy we have to start from scratch and assume nothing," Munoz-Furlong says. "We always have to be ready that it might come back."
Food allergies account for 30,000 emergency room visits and between 150 and 200 deaths a year in the United States. Many of those are believed to be the result of peanuts, Munoz-Furlong says.
What To Do
For more on food allergies, try the Food Allergy and Anaphylaxis Network or the U.S. Food and Drug Administration.
