Young Children May Outgrow Peanut Allergies Along with Other Food Allergies, According to Research at The Children's Hospital of Philadelphia

02/15/2001

PHILADELPHIA, Feb. 15 /PRNewswire/ -- Having a child with peanut allergy strikes fear in the hearts of parents because it is one of the leading causes of fatal and near-fatal food-induced allergic reactions. This has ignited a heated controversy about banning peanuts from school cafeterias and airline snack trays.

Now there is new -- and perhaps reassuring -- evidence that some children may outgrow this life-threatening reaction to the legume, according to research at The Children's Hospital of Philadelphia. The findings were published in the December 2000 issue of the Annals of Allergy, Asthma & Immunology and are part of an ongoing study at the hospital.

Unlike allergies to other foods such as milk and eggs, which are generally outgrown by the time a child is five years old, conventional thinking is that sensitivity to peanuts lasts a lifetime. This study is among the first to challenge that assumption. "It represents a shift from the idea that no children outgrow peanut allergies to the reality that this allergy may indeed resolve in some children," said the study's lead author, Jonathan Spergel, M.D., Ph.D., associate physician in the Section of Allergy at Children's Hospital. Co-authors include Nicholas A. Pawlowski, M.D., Chief, Section of Allergy, and Janet Beausoleil, M.D., associate physician in the Section of Allergy.

The report centered on 33 patients who showed a clear clinical history of peanut allergy and positive skin tests. Feeding the children the suspected peanut allergen, a procedure known as an oral challenge, was done up to five years after their initial evaluations.

Dr. Spergel stressed that people with peanut allergies should be challenged only in a medical setting under controlled conditions to see if they have outgrown their allergy. "That way, if someone is going to have a full-blown anaphylactic reaction requiring immediate treatment, we can prevent it from becoming a life-threatening reaction at the first sign of trouble."

In the study, the researchers carefully fed the children tiny amounts of peanut starting with 1/40th of a teaspoon until the patient showed a reaction or tolerated two teaspoons of peanut. Reactions included hives, flaring of dermatitis, vomiting/diarrhea, respiratory symptoms or the beginnings of anaphylaxis, marked by throat swelling, difficulty breathing and a drop in blood pressure.

Nineteen patients continued to react to peanuts, while 14 children had a negative reaction to the challenge. These "resolvers," who ranged in age from 18 months to eight years old, had milder initial reactions to peanuts. They were more likely to have hives rather than breathing problems or dangerous throat swelling when ingesting peanut butter for the first time.

"Our findings suggest that at least some of peanut-sensitive children will outgrow their peanut allergy. We are working hard to find out just how many will be this fortunate," said Dr. Spergel. Once the allergy is gone, it does not reappear later in life, he added.

But he stressed that this is just the beginning of unraveling the peanut-allergy mystery. "We cannot predict all who will be sensitive by using any current tests, nor can we predict how they will react," he said. "We are hoping to identify the features that will predict who will outgrow the allergy, and when it might happen." Skin and blood tests are limited in their usefulness because a positive test only means that a person may react.

Another goal is to develop an effective treatment for peanut allergy. "At present, there are no treatments -- no allergy shots or pills -- that can prevent a reaction," says Dr. Spergel. "The only course is to avoid suspect foods."

Other points presented in the report included:

-- Other studies have shown that peanut allergy occurs in less than one percent of the population in this country. Nearly all occur in people under 15 years of age.

-- Other studies have also shown that, as peanut products become more common in the diet, peanut allergy is being observed at earlier ages. Peanut allergy is also seen in very young children due to sensitization in utero and infancy via breast milk, if the mother eats peanuts.

-- Refusal to eat peanuts can be a sign of an allergy. In this study, of 13 patients who refused to eat peanuts and who had positive skin tests, 38 percent were documented to have clinical sensitivity by a positive challenge. It is possible that the patients had been avoiding this food since they knew it would make them sick. However, refusal to eat peanuts "should not be viewed as an indicator of a true peanut allergy unless a challenge is performed," said Dr. Spergel.

-- Among patients with peanut allergy, the most common reaction to peanuts involved the skin, with dermatitis or hives.

-- A potential indicator of the possibility to become tolerant of peanuts may be the size of the initial reaction noted on the skin test. The smaller the reaction, the more likely the child may outgrow the allergy, the study suggested.

-- In general, patients who have had an anaphylactic reaction to peanuts appeared to be less likely to have resolution of their peanut allergy.

Founded in 1855 as the nation's first pediatric hospital, The Children's Hospital of Philadelphia is ranked today as the best pediatric hospital in the nation by a comprehensive Child Magazine survey. Its pediatric research program is among the largest in the country, ranking second in National Institutes of Health funding.

CONTACT: Erin McDermott of The Children's Hospital of Philadelphia, 215-590-7429.