Can people allergic to nuts still eat some types?

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PEOPLE who are allergic to one type of tree nut, such as cashews, may not be allergic to all other kinds of tree nuts, though they are often told to avoid those nuts, a new study finds.
The study’s authors suggest that people who have developed allergic symptoms in the past to one tree nut, and who have been avoiding eating all other tree nuts based on medical advice may wish to undergo a properly supervised “oral food challenge” test, to see if they are truly allergic to other tree nuts. However, more research is needed to confirm the new findings.
Tree nuts are a group of eight nuts: almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pistachios and walnuts. Researchers in the new study found that 76 percent of the participants who had an allergy to one type of tree nut could pass an oral food challenge test with a different tree nut. This test involves eating very small amounts of a food under medical supervision to see if the individual develops any symptoms of an allergic reaction, such as wheezing, a rash, an upset stomach or facial swelling.
An oral food challenge is a closely supervised medical procedure, and people with known allergies to tree nuts or peanuts should not be experimenting with eating nuts on their own, because this could trigger a severe allergic reaction known as anaphylaxis.
Passing an oral food challenge test is considered the most accurate way for people to demonstrate that they do not have a food allergy, according to a statement from the American College of Allergy, Asthma and Immunology, an association of allergy specialists that publishes the medical journal in which the new study appears.
“We found that patients with tree nut allergies can be allergic to one nut but be tolerant to another tree nut,” said Dr. Christopher Couch, an allergist at the Allergy Asthma Clinic, Ltd. in Phoenix, and the lead author of the study published today (March 27) in the journal Annals of Allergy, Asthma and Immunology.
Two other tests, a blood test and a skin-prick test, are also used to diagnose food allergies. However, a positive result on either of those tests does not always indicate that a person is truly allergic to the food being tested, Couch told Live Science. A food challenge is the next step to confirm the allergy, he said. About 1 percent of children in the United States are allergic to tree nuts, according to an estimate published in the journal Pediatrics in 2011.