Why does someone who is allergic to peanuts have to avoid all nuts?

[neolara]

My dd (2yo) was seen at the allergy clinic yesterday and reacted positively to peanuts on a skin prick test. We were given a handout which advised that she should avoid all nuts. Stupidly, I forgot at the time to ask why. Is it just that at some point they might have come into contact with peanuts?

My dd has only had one reaction to peanuts so far, but her face swelled after getting a spec of peanut butter on her hand for about 3 seconds, so I think she is probably quite sensitive. She has previously also reacted to cashews although this did not come up positive during the prick test. She'll be rechecked in a few weeks. Obviously I'm going to be obsessively checking for peanuts now, but I'm just wondering how careful I need to be about other nuts. She is predominantly veggie so nuts are potentially a good source of protein.

Is it because they are usually processed on the same 'line' at factories and so a high risk of cross contamination. I remember making my own nutella, grinding the hazelnuts.

My dd is allergic to peanuts and we weren't to that four years ago. Peanuts are not a nut.

However, despite being a great eater who will try anything she does not like nuts. She says she feels as if she can't eat them. It's like her body is telling her not to eat them in a way. She has them in pesto and things when she can't taste them.

She never ate the nutella though!

Thanks savoy. Any one else got any ideas?

It is because of the risk of cross contamination.

I was told at our last hospital appointment that a peanut allergic child has a 40% chance of becoming allergic to tree nuts, and he gave us that reason for avoidance of all nuts...

DS's is allergic to tree nuts but had only a slightly raised result to peanuts (he had never come into contact with either, but I did eat some tree nuts while I was pregnant). His allergy paediatrician said to avoid ALL nuts for the reasons already given above by savoy, trixymalixy and Lilpickle. She said he was likely to become sensitised to peanuts in the future, and that there was a high risk of cross-contamination.

It's not just about the risk of contamination, it's about proteins.

Peanuts are a legume but have some proteins very similar to tree nuts. Other proteins they share with beans, peas, lentils etc and some proteins are specific to the peanut.

It is the proteins in a food that an allergic person reacts to. So for peanut allergy you get:

• some people that are allergic to peanuts and tree nuts.

-some people who react to peanuts and other legumes. -some people who are just allergic to peanuts (or to peanuts and other unrelated things like cows milk).

My ds1 was in the third group but we never gave him other nuts due to the risk of contamination. He was young and we hoped he would grow out of his allergy, which he did. If he hadn't I suspect we would have introduced tree nuts at some point. He always ate legumes.

If your lo has already reacted to cashews then I'm afraid there is a fair chance she is group 1 ie allergic to the protein found in peanuts and some other tree nuts. Given her sensitivity I would really recommend you do not try at home but ask for a food challenge at the hospital if you feel you would really like to know. One nut in particular you might want to ask about is almonds because their proteins are a bit different from other nuts, so even most people who can't eat tree nuts etc can eat them.

Coconut should be fine. To quote our consultant 'coconut is not considered as a nut, in allergy terms'.