A new study finds certain tests for tree nut allergies may not be accurate and many people may be over diagnosed.
To reach his conclusions, Couch and his team investigated medical records belonging to 109 people with documented peanut allergies, who also tested positive for allergies to other nuts.
"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.
"What people with a nut allergy need to remember", Spergel said, "is that when they are buying nuts be careful not to buy mixed nuts".
An oral food challenge is when you eat tiny pieces of tree nuts in a controlled medical setting. Delayed oral food challenge was defined as longer than 12 months from the time of an sIgE level lower than 2kUA/L.
Nut allergies are being over diagnosed because many skin and blood tests can not be relied on, a study found.
Moreover, study results showed nearly none of the people with peanut allergy were actually allergic to almonds, cashews, walnuts and hazelnuts. They're grown underground, not on a tree.
'Tree nut allergy should only be diagnosed if there is both a positive test and a history of developing symptoms after eating that tree nut'.
According to research leader Dr. Christopher Couch, from the University of MI, once their tree nut allergy has been detected via a blood test or a skin prick test, most people resolve to stop eating nuts altogether, and they do so unnecessarily.
Amena Warner, head of Clinical Services at Allergy UK said oral food challenges were "the gold standard" of allergy testing, but not always available.
Researchers looked at more than 100 participants with a known tree nut allergy and found 50% passed an oral food challenge to other tree nuts without a reaction.
The study found more than half of people diagnosed as allergic to one type of tree nut were able to pass oral food challenges to other tree nuts with no reaction - meaning they are not allergic to that nut.
Symptoms of tree nut allergies may include abdominal pain, diarrhea, nausea, vomiting, itching of the mouth, throat, eyes, or skin, shortness of breath, and - in severe cases - anaphylaxis.
"Previous studies suggested people with a tree nut allergy, as well as those with a peanut allergy, were at risk of being allergic to multiple tree nuts", said allergist Dr. Matthew Greenhawt. They were then closely monitored for any allergic reactions.