Some clarity: does peanut allergy mean avoiding ALL nuts?

One of the quandaries we faced in the early days following our son’s peanut allergy diagnosis was whether he needed to avoid tree nuts as well as peanuts.

To explain: peanuts are legumes (in the same food family as lentils and peas), whereas tree nuts include almonds, hazelnuts, walnuts, cashews, pecans, Brazil nuts and pistachios. A person can be allergic to peanuts, tree nuts or both. You might be allergic to one type (or several types) of tree nut, but be able to eat other types of tree nut without any problem.

My son (D) was diagnosed with a peanut allergy after having a severe anaphylactic reaction to a peanut cookie. He had no other known allergies at that point. At one of our first hospital appointments we were advised to avoid ALL nuts to minimise:

  • The confusion risk. It is simpler to say to family, friends, nursery, school, babysitters etc that he is “allergic to nuts”. As the recent furore over the mislabelled EH Booths monkey nuts illustrated, many people do not know that peanuts and tree nuts are two different things. So, if we were to say to a carer, “Don’t give D peanuts, but other nuts are fine”, s/he might be confused as to whether a food containing, for example, “ground nuts” was safe. It’s easier to simply impose a blanket ban and say “no nuts”.
  • The cross-contamination risk. As I understand it, many manufacturers use the same machinery to process all types of nuts. So, if a manufacturer makes a peanut-containing biscuit on the same machinery as a hazelnut-containing biscuit, then the hazelnut cookie is a high risk product for purely peanut allergic people, as it might contain peanut traces.

In a similar vein, Dr Andrew Clark (from Addenbrooke’s Hospital, Cambridge) in a Q&A piece for Mumsnet in April 2010 said:

“I advise to avoid all nut types, not just the one you are allergic to. The logic is that manufacturers are not great at separating nut types within products. All they have to tell you is that there are nuts in a product, they are not obliged to spell out exactly which types are present.* Even if you buy bags of single-nut types, remember that the manufacturers probably deal in all the other nut types as well and contamination is a possibility”

(* If “Peanut” is an ingredient, “peanut” must be stated on the ingredients list – see Deciphering UK food allergen labelling law. Dr Clark was discussing tree nuts.)

Our first doctor’s view was that skin prick testing for tree nuts was unnecessary, as (because of the confusion and cross-contamination risks) we should be avoiding all nuts anyway.  Although I understood the logic, having as much information as possible about the extent of D’s allergies helped give me, personally, some peace of mind. So we went ahead, and he was skin prick tested for tree nuts. After the tests revealed only a peanut allergy, a second doctor advised us to reintroduce tree nuts into D’s diet, one tree nut at a time, every three months or so. Unsure of what to do, we continued to avoid all nuts for the time being.

Having now double checked this with the hospital, we have decided to continue avoiding all nuts. Becoming nut-free wasn’t a huge lifestyle change for us. However, had the rest of the family been eating a diet rich in tree nuts (for example, on account of our ethnic background or, say, because we were vegetarian), then, if we wanted to reintroduce tree nuts to D’s diet, the second doctor’s advice would have been the way to approach this.

I was concerned that, by continuing to avoid all tree nuts, we would actually be increasing D’s risk of developing allergies to tree nuts (whereas currently he is only known to be peanut allergic). I understand there is no definitive answer to this as, at the moment, there is no medical evidence showing that tree nut avoidance will lead to a tree nut allergy. So, as re-introducing tree nuts would carry the risk of confusion and cross-contamination, without offering any definitive benefit, we are staying completely nut free.

Further information


  1. Just stumbled across this website whilst searching for nut-free advent calendars. My son is now 19, and was first diagnosed with a peanut allergy aged 4. We avoided all nuts and nut-traces for about 10 years, but he then started to eat chocolate with tree nut trace warnings as the original blood tests had shown peanut-only allergy, and we felt it was very low risk. Subsequent testing showed that he has now developed an allergy to hazelnuts. So back to the very cautious approach of avoiding all nuts/traces. So based on our experience, multiple allergies can develop over time and I would advise caution. I watch with interest the clinical de-sensitisiation studies which are being conducted at Cambridge, the results look encouraging.

    1. Hi Jan – thanks very much – that’s very interesting to know. I imagine I’ll be extremely nervous when my son is next skin prick tested, in case he’s developed further allergies to tree nut(s). And, absolutely about the desensitisation studies – fingers crossed. Louise

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