Q:

12/5/2012
In peanut allergic children with negative tree nut skin testing, I recommend that they ingest tree nuts in safe (non-choking hazard) forms if their parents desire that their child eat tree nuts and clearly understand peanut/tree nut cross-contamination issues. I feel that this improves quality of life and may (theoretically) protect against the development of tree nut allergies.

I have colleagues that restrict tree nuts in the same situation, due to the existing data that 1/3rd of children of peanut allergy have or may develop tree nut allergy. They feel that the patients that I encourage to eat tree nuts may be at significant risk for a reaction to tree nuts in the future.

I was hoping that you could provide some insight, as we would prefer that our advice be fairly consistent between different members of our practice. Thanks for your time!

A:

Thank you for your inquiry.

The approach to the issue that you posed is based on one’s personal philosophy regarding patient care, and therefore there is no “right” or “wrong” approach. Your rationale is reasonable as is the position taken by your colleagues. My own personal approach is to follow that suggested by Dr. Hugh Sampson.

A question similar to yours has been submitted to “Ask the Expert” previously, and Dr. Sampson’s response to it has been posted on our website. For your convenience, I have copied his approach to this issue below, along with the previously submitted similar question on this topic.

Thank you again for your inquiry and we hope this response is helpful to you.

Empiric avoidance of tree nuts in a peanut-allergic child
Posted on 8/8/2011
Question:
When evaluating a child for an immediate reaction to peanut using skin prick testing, is it reasonable to also "screen" for allergies to other tree-nuts (even without history of tree nut ingestion or adverse reaction with tree nut ingestion?), given that approximately 1/3 of patients with peanut allergy have been reported to also have a clinical food allergy to tree-nuts?

To my mind, screening children for allergies to tree nuts on the basis of a confirmed peanut allergy is probably not wise due to the possibility of false positive skin testing, however I have colleagues that test for all potentially cross-reactive foods, even if there is no history of reaction to those foods. Your opinion would be greatly appreciated.

Answer:
Thank you for your recent inquiry.

This question has been posed to our website on several occasions. The answer given by Dr. Hugh Sampson, which I have copied and pasted for you below, is, in my opinion, the most reasonable approach to the issue you pose. Since, as Dr. Sampson states below, automatic avoidance of tree nuts is suggested for children who have had a documented allergic reaction to peanut , and since tree nut testing would not alter this approach, the strategy which you favor can certainly be supported. It is the strategy that I normally use.

However, you will also note that at the bottom of this response , this strategy is based as much one's philosophy as on evidence-based medicine, and therefore one cannot, in my opinion, be dogmatic over the issue or state that there is a clear “right or wrong” approach to the question. But, as noted, I would personally favor your viewpoint. Nonetheless, I would not be in any way critical of the opposite approach.

Thank you again for your inquiry and we hope this response is helpful to you.

Previous Question and Response:
Question:
" If you have a toddler who is allergic to peanut supported by history and skin testing, should they empirically avoid tree nuts despite there different protein structures since we know tree nuts might be sensitizers- and vice versus, tree nut allergic....avoid peanut?"

Dr. Sampson's Response:
"If a toddler has a clear-cut, recent reaction to peanut and a positive skin test, I generally tell the parents that they should eliminate peanuts and tree nuts from the child's diet. [I also obtain a peanut-specific IgE level so that I can get some idea of whether this toddler may fall into the 20% of young children who will outgrow their peanut allergy] There is little evidence to support the notion that tree nuts 'cross-react' with peanuts and therefore avoidance for this reason seems unjustified. However, two other factors that support tree nut avoidance must be considered. (1) Studies indicate that about 35% of American toddlers with peanut allergy will have [or develop] concomitant tree nut allergy. (2) In a young child, it is very confusing to distinguish the difference between peanut and 'safe' tree nuts, since many adults refer to both as nuts and are unaware of situations where peanuts may be included with specific tree nuts. We have seen too many accidents where a child receives peanut-containing products because of misidentification, cross-contamination, or substitution with some peanut product. Consequently we think it is safer to avoid tree nuts until the child is old enough to understand the nuances of avoiding peanut contaminated foods. We often will skin test the child to various tree nuts [and obtain nut-specific IgE if the skin test is positive] so that the parents will know whether the child is likely to experience an allergic reaction if the child inadvertently ingests a tree nut-containing food"

I favor this policy, and would also employ it in the converse state - that is, "when a patient is known to be allergic to tree nuts, should they avoid peanuts?"

This of course is as much a philosophical as a scientific, evidence-based answer. But the reasons that Dr. Sampson cited are quite cogent, and represent the safest course of action.

Thank you again for your inquiry and I hope this information has been of help to you.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology