Nine percent of children allergic to almonds, pecans,
cashews and other tree nuts outgrow their allergy over
time, including those who've had a severe reaction such as
anaphylaxis shock, according to researchers at the
Their study, reported in the November issue of the
Journal of Allergy and Clinical Immunology, also
found that clinicians can use blood levels of tree nut
antibody, TN IgE, as an accurate guideline in estimating
the likelihood that a child has outgrown the allergy.
"What's crystal clear is that children with these
allergies should be regularly re-evaluated," researchers
concluded in the study.
"Allergic reactions to tree nuts as well as peanuts
(which are not nuts but legumes) can be quite severe, and
they are generally thought to be lifelong," senior author
Robert Wood, director of the
Allergy and Immunology at the Children's Center, said.
"Our research shows that for some children, however,
lifelong avoidance of these nuts, found in countless food
products, may not be necessary."
In the United States, an estimated 1 percent to 2
percent of the population is allergic to tree nuts
(almonds, pecans, walnuts, cashews, Brazil nuts, hazelnuts,
pine nuts, pistachios and macadamia nuts), peanuts or both.
Wood and colleagues previously reported that as many as 20
percent of children outgrow peanut allergy and recommended
that allergists periodically retest their patients. The
current study explored whether the same held true for tree
Wood and colleagues evaluated 278 children, ages 3 to
21 years old, with a known allergy to tree nuts. Nine
percent passed oral food challenges, the standard test to
prove a child has outgrown a food allergy. Fifty-eight
percent of children with TN IgE levels of 5 kilounits per
liter or less also passed the challenge.
"These findings give allergists a safe guideline in
deciding whether to advise their patients to continue
avoiding tree nuts or whether it's time to try an oral food
challenge to see if they've outgrown the allergy," Wood
said. He cautioned that oral food challenges should be
presented only under the close supervision of an
The study also found that, of children allergic to
both peanuts and tree nuts, those who had outgrown their
peanut allergy were more likely to outgrow the tree nut
allergy. Children who are allergic to more than one type of
tree nut are unlikely to outgrow their allergy.
The study was funded in part by the National Institute
of Allergy and Infectious Diseases.
—Stacy Vernick Goldberg