Mixed nut challenge - what to expect

[gettingridiculous]

My DS 7 had a skin prick test (his last one was when he was 18 months old). At his first SPT he showed a sizeable reaction to cashew and pistachio and smaller reactions to most other nuts (including peanut and pine nut).

Yesterday, the only reaction was to Cashew and it was 3mm in diameter, slightly smaller than the normal reaction that they deliberately provoke to check the immune response is working (if that makes sense?!)

The allergy doctor has now ordered a mixed nut challenge on the ward in a couple of weeks time. I'm very nervous about it.

My DS has only had 2 reactions (hives) and these led us to the first SPT. Since then, we have tightly controlled his diet and he has therefore not had any exposures.

Has anyone gone through this? I am wondering why they don't just check with the cashew first? Why do they go for "mixed" nuts - how do they ascertain what causes a reaction if it's in a mixture?

TIA

[trixymalixy]

I don't know for definite, but it may be because cross contamination is so common with nuts that it's highly likely that a pack of say cashew nuts is contaminated by particles from many other types of nuts as they will be processed in the same factory.

Even if your DC passed a cashew but test but was still allergic to other nuts it'd be far too risky to ever eat a cashew nut due to cross contamination.

[gettingridiculous]

Yes, my thoughts were that even if she was only allergic to cashew the advice would remain to avoid all other nuts because of cross contamination risk. But I think the Dr was intimating that because the reaction on the SPT was so small (to the cashew nut only) that it might be just that he had been "sensitized" but was not necessarily allergic?? Anyway, all will be revealed at the nut challenge. I've read a few things on the anaphylaxis site about nut challenges and they speak of putting in a cannula so they can get the drugs in quickly should there be a reaction. Does anyone know if this is the case? The challenge will take place at Glasgow's Yorkhill.

[trixymalixy]

I've been through several food challenges at Yorkhill, none involved a canula, but they were not nut challenges so not sure if the protocol is different. However I'm fairly certain that there have been other children having nut challenges at the same time that didn't have a canula.

[gettingridiculous]

Thanks trixymalixy - I won't mention the canula for now!

[kissmyheathenass]

Ds had nut challenges - separate nuts not mixed. First it was peanuts and he was fine - happily munching a small pot of nuts by the afternoon. We were told he needed to leave one month till the next challenge which we did. The second one was cashew, he has a tiny amount - around 1/4 a grain of rice in size - and went into anaphylactic shock. It was so rapid, it was awful. They got medicine into him very quickly by needle as no canula had been inserted. They were talking of getting the throat openers for him but he didn't need them in the end. That was about 2 years ago and we still haven't had the courage to go for the third challenge which is hazelnut.

[trixymalixy]

I'm not surprised kiss, that sounds terrifying!! I wouldn't be keen on doing another challenge either.

A quick google suggests that a cannula is only used if there have been previous severe reactions.

[gettingridiculous]

Wow kissmyheathenass that sounds absolutely terrifying! Your poor son and you having to watch Had he ever had an anaphylactic shock before? Am guessing not as I would imagine they would have had the cannula in if he had. I've just had the letter for the appointment and it specifically says its for "mixed nut challenge without cannula"

Like trixymalixy I too am not surprised you've not done the next challenge. Out of interest, how old was your son when he had the challenge?

[pashmina696]

Please let us know how it goes. best of luck to him.

[kissmyheathenass]

gettingridiculous, ds was 12 when we did the challenge. Let us know how you get on. Despite the trauma of the cashew nut test, I would prefer him to have the last one (hazelnut) so at least we are a little bit more informed.

Cashews are generally quite easy to avoid as long as we don't go to Asian restaurants. A boy died last week after eating ribs from a Chinese takeaway. It terrifies me.

[gettingridiculous]

Thanks pashmina696 will let you know how we get on.

I heard about that boy kissmyheathenass - it just brings it home doesn't it? Terrifying.

Cashews tend not to be in so many things but you just never know. I didn't know they were in pesto until my DS had a mild reaction. I worry that they get put into things instead of peanuts because people don't realise that they can be as dangerous as them. In fact, I've read, that a cashew allergy is more prone to full-blown anaphylaxis than even peanut?

I deliberately didn't eat peanuts during my pregnancy with DS but did eat cashew nut butter instead. My first child has no allergies and I certainly ate nuts during that pregnancy. There's no rhyme or reason for it but I can't help thinking there was a definite connection between me regularly eating cashew during DS's pregnancy and then him having a particularly strong allergy to the cashew nut.

I'm not holding my breath that we're out of the woods on the allergy front. The small reaction was from cashew so that must mean it's still there. I don't know how more relaxed I could be about things if it was JUST cashew - our hospital still prescribes a No nuts at all approach even if it is just one nut but I guess I could be slightly more relaxed about things that say they may contain traces?

[pashmina696]

I avoided peanut too in pregnancy - but did snack on cashews and pistachios, i also ate houmous and DS1 is highly allergic to both these nuts and sesame - he has avoided any contact yet to the nuts, but the sesame reactions have been awful. I have read enough about cashew allergy to be suitably paranoid about it - and its so poorly understood - BA often have mixed nuts now instead of peanuts on flights... many indian curries are loaded with ground cashew...

[gettingridiculous]

Just updating as promised. When we got to Yorkhill the allergy nurse straight away said, I'm going to test for cashew on its own. I said I could see the logic of that. So DS had the mixed nuts taped to one arm and a single cashew to another - 15 minutes later, no reaction. Nurse then took a cashew nut and rubbed it all over his lips - within seconds a rash appeared around his mouth and chin and his top lip began to swell - nut challenge stopped and Piriton administered. Swelling went down and hivey rash faded over the next half hour. So no doubts there - the cashew nut allergy is alive and well

The nurse said the advice remains the same - avoid all nuts. She said that if my DS ate other nuts it would be more likely that another nut allergy would arise especially as there were reactions on the initial skin prick test. And obviously there's the risk of cross-contamination. Another appointment with consultant in 18 months but she doubts they will try another challenge as if he hasn't grown out of it at 7 he's not likely to.

We don't know whether we will be more relaxed with "may contain traces of peanuts" warnings on products. What is the likely-hood that something may contain a trace of a peanut that contained a trace of a cashew?? Also I suppose he might have shown an allergic reaction to some other of the nuts that might not have shown up in the latest skin prick test? All academic now.

Anyway, at least it wasn't too dramatic - just the usual rashy/swelling. I hadn't had great hopes of it all going away but had allowed myself the odd fantasy that we would be free of it!