Confused about strength of reaction on allergy test...

[IHeartKingThistle]

DS (2) has had a blood test for nut and seed allergy. The letter that's come back says that he is allergic to peanuts, cashews, pistachios, sesame and lentils.

On the scale of 1-6 the highest reaction his blood had was a 2, and some of the reactions were much lower. BUT the letter said that that doesn't mean that the allergy is mild. Does anyone know about these tests?

The only reaction he's had to these foods in the past is a rash around his mouth (he has eczema which also flares up).

So could this reaction get more severe? I'm just a bit confused as to how careful I need to be. I had myself convinced it wasn't a genuine nut allergy (I know, I'm an idiot) so I'm now feeling very sad for him. Do I have to avoid food that says it may contain traces of nuts, or that comes from a factory that uses nuts? This is a whole new territory for me...

Hello IHeartKingThistle! Unfortunately allergy tests, both blood & skin prick, are notoriously unreliable and you can get lots of false positives and false negatives. They are however a useful tool in the diagnosis of allergies, like pieces of a jigsaw puzzle really. The fact that your DS has had reactions to these foods in the past is the biggest indicator that he has an allergy and the blood tests have been done to try to confirm this. Normally, level 2 and above is considered evidence of a specific allergy but some can have a RAST result of 1 and still in fact be very allergic to something if they ingest it. Has DS had skin prick tests done too or just the RAST?

By the way, you're not an idiot, you're just starting to find your way through the maze that is the world of allergies and believe me we all make mistakes along the way (and blame ourselves for everything but that's part of a being a mum I think!). I'm afraid allergy tests can't tell you how severe a reaction may or may not be and it's therefore best to be very cautious. As for the issue around 'may contain' or 'produced in a factory' etc that's a difficult one as I know that many people have had conflicting advice from different professionals on whether or not these foods are 'safe'. It's a minefield because it's so difficult to assess the 'risk'. Some manufacturers stick 'may contain' on all their products simply because they're scared of litigation or just too lazy to make sure their processes don't have any cross-contamination while others try to be honest about the fact that there may be a genuine risk of contamination. I know for example that if Cadbury's say 'may contain nuts' there is a quite a significant risk as they use the same machines to produce certain nut choc products as other non-nut products, they just clean the production pipes with melted choc so there could easily be some bits of nut left behind. In the end, it's a personal decision and a very difficult one. My husband is allergic to nuts but has never had a 'severe' reaction 9in his opinion) and he chooses to eat things that say 'may contain nuts' and I have to admit that I do give my DS foods that say 'may contain milk/wheat/egg' because his diet is so limited that I feel forced to take the risk. But I'm always worried that one day I will come to regret that decision in the worst possible way.

Thanks for taking the time to reply. It seems that it might be more complicated than I thought then

My dd (2 yo) was recently seen at Addenbrookes. She has had skin prick tests for nuts and tomatoes. She reacted to peanuts. The consultant said that the skin prick test does not give any indication of how severe an allergy is, simply that an allergic response occurs. She said that the biggest indication of how severe a response is likely to be, is previous responses. So in our case, our dd developed hives and swelling when she ingested tiny amounts of peanut. This, according to the doctors, suggests that she is probably very allergic. In any case, the advise was to avoid all nuts as their may be cross contamination and also because response can vary according to other factors e.g. if she had an infection she would be more likely to react severely. She said that the risks of eating things that contain "traces of nut" were very small, (similar to being involved in a road accident) but that all parents need to make up their own mind.

In your shoes, I would avoid all nuts, also sesame and lentils. I would check all food packaging for allergy labelling and I would do it every time your ds eats something, even if he has had it before and been OK. This is because recipes and manufacturing methods change. This is particularly important for biscuits and cakes. (Also cake decorations / sprinkles sometimes include peanut oil). I would not give your ds anything from a deli counter because of the risk of cross contamination. Also, apparently Indian and Chinese take away foods are very risky for nut allergy sufferers, so I would avoid these like the plague.

I would go back to your doctor and ask for an epipen - don't be fobbed off. I would ensure that the person caring for you ds at any particular time (e.g. you, nursery staff etc) carries a bottle of piriton or equivalent and an epipen at all times. I would also ask the doctors to explain the results in more detail so you understand them properly and I would want them to know how they are going to review your ds's allergies in the future.

I know it sounds scary, but we are now a few months down the line and it's been much more manageable than I'd imagined. The main difference to our lives has been that I just check food labelling religiously before my dd eats anything. Good luck with it all.

Very good advice from neolara. Just wanted to add that baby & toddler vitamin drops sometimes contain peanut oil believe it or not so watch out for that one.

Blimey. Def going back to GP then. Thanks so much. He hasn't reacted to anything for ages after we stopped giving him houmous and lentil soup (he wasn't having nuts anyway). The biggest reaction he's had was to pesto - I'm guessing pine nuts?

But he did definitely react to something last week and I think it was a cracker from a mixed box of 'crackers for cheese'. I didn't check the box - there were definitely no nutty or sesame ones - but I bet there was some sesame knocking around in them somewhere. I'm an idiot. It wasn't a strong reaction, just red marks round his mouth, but he's had the first eczema flare-up in ages and it's taken all week to get under control.

The question I'm scared to ask is - are his reactions going to stay mild? How likely is a more severe reaction further down the line?

Nobody can say how likely it is but you have to work on the assumption that his next reaction could be serious, as scary as that my be. It's better to assume the worst and put measures in place to manage the risk.

By the way, pine nuts are seeds rather than nuts but it's often only the more expensive pestos that contain pine nuts, many contain 'proper' nuts like cashews or walnuts so definitely one to avoid especially as your DS has a problem with seeds too.