Corey’s Introduction to Tree Nuts part 1: skin prick tests

by amanda
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Corey’s Introduction to Tree Nuts

Before Corey’s food allergies, tree nuts were never a focus in my food universe. Sure, occasional almonds in chocolate added a nice texture. Indulging in cashew biscuits during Chinese New Year is also a must. Beyond these, I never cared about which nut was which.

I never imagined that one day, tree nuts could be a health hazard to my kids.

So naturally we were surprised to learn that Corey’s severe allergies to peanuts (among other foods), meant he has a good chance of being allergic to tree nuts too.

Along with peanuts and shellfish, tree nuts are one of the food allergens most often linked to anaphylaxis — a serious, rapid-onset allergic reaction that may be fatal. Between 25% and 40% of individuals who are allergic to peanuts also react to at least one tree nut. Tree nut allergy usually lasts a lifetime; fewer than 10% of people with this allergy outgrow it.

American College of Allergy, Asthma and Immunology

Oh, and just to be clear, peanuts are legumes, like soy. They are not nuts at all. And coconuts are actually a fruit, although it too is fast becoming an allergenic food. HOW CONFUSING! Anyhow, explaining those things are a post for another day. For now, we turn our attention back to tree nut allergies.

Noticed the BOLD text that says ‘at least one tree nut‘.

My first thought was, how many tree nuts are we talking about?

So I googled and opened Pandora’s Box. The following list are TREE NUTS as listed in google:

  1. almonds
  2. brazil nuts
  3. cashews
  4. hestnuts
  5. filberts/hazelnuts,
  6. macadamia nuts,
  7. pecans,
  8. pistachios,
  9. shea nuts
  10. walnuts.

Mama’s got her work cut out for her to find out whether my baby is allergic to any of these 10 tree nuts- but investigate we must.

But first..

Before I discuss the finer details on how we introducing tree nuts to Corey, I need to state a few important disclaimers.

Always, ALWAYS consult a proper allergist BEFORE ALL ELSE.

My experience is unique ONLY to me. Allergic reactions, especially food allergies, are highly variable. Each person’s histology of allergic reactions is different as well.

Anything I expose Corey to is in close consultation with our allergist. Any tests we do or provocation done is under strict guidance of our allergist. I strongly urge any parent of allergic children to do the same.

If our allergist tells me not to sneeze, I will hold it in. Although that would probably be very uncomfortable. But you get the idea.

End 2018:
Our first Tree Nut SPT


Our first tree nut skin prick test was done some time at the end of 2018. Corey’s eczema was under control. His growth was good and he was thriving in school. I started to entertain thoughts of travelling in 2019.

But to even consider travelling, I wanted to have a sense of our risk of allergic reactions to tree nuts. I already knew his peanut allergy is huge. But we had no clue whether he is allergic to tree nuts.

After discussing with our allergist, we decided to start with a basic skin prick tests of the most common tree nuts. So we went ahead to test for Almonds, cashews and hazelnuts.

Step 1: Extracts of each chosen allergen (cashew, hazelnut and almond) are placed on good, clean skin. Along with a histamine control (the + mark) and a saline control. P

Step 2: Then a teeny tiny needle is used to poke the middle of the extract. This induces a reaction from the skin. It is virtually painless and hardly feels like an ant bite. Then we wait 15 minutes for the skin reaction (size of the skin wheal) to happen.

Step 3: After 15 minutes, we measured the size of each reaction and the technician notes it down in a result slip. These results are then discussed with our allergist.

Our first Tree Nut Skin Prick test Results


and these are GOOD results indicating low risk

Interpreting skin prick test results are about using it to gauge the risk of reactions.

The skin is the body’s first defence system against any allergen. So it makes perfect sense to understand how the skin would react if it comes into contact with the allergen.

‘W’ on the result slip means skin WHEAL size. The size of this skin wheal is significant only in relation to the histamine control (your body’s natural reaction without the allergen).

In the results, we see that the histamine control is 3, while the almond and cashew are 1 and 2 respectively. And hazelnut is 3.

What we can interpret from these results is there is a lower risk of a serious reaction from being in contact with these 3 tree nuts.


While the skin is pretty reliable in telling us what will happen if the allergens comes into contact with it on the surface. It says nothing about what happens an hour later after the ingested allergen has gone down our throats and into our gut.

Because our immune system defense reactions includes not only rashes and hives, we need to consider that other allergic reactions could occur later on. Reactions such as vomiting, diarrhea, stomach pains, shortness of breath can all occur in the absence of a skin reaction to an allergen.

Thus the true test of whether a person is truly allergic to any foods is through eating the allergen. So while the results indicated low to negative reactivity to these 3 nuts, it might be a different story if Corey actually ingests them.

Therefore, in the next Part 2 of “Corey’s Introduction to Tree Nuts”, I will discuss how we went about doing a food provocation test and the results of these 3 nuts.

For now, let’s enjoy the happy results and celebrate by making some monkey faces

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