Help with IgE results??

[2rubies]

I just pulled out the grainy copy of blood test results we had done on my youngest almost a year ago. The pediatrician's office ordered the test because he had what we thought was an anaphylactic reaction to something in a smoothie I made. I was handed the results and told that "nothing came up positive" like that was good news. Three months later, he had another reaction and tested positive to walnut (there is not a single tree nut tested on the original blood work).

Anyway, now I'm wondering about these results. What the heck do they mean?? He has lots of "class 0" results, and a lot of "class 2" results. The "class 2" are for things like wheat, rye, barley, corn, peanut, soy, orange, potato, malt, and lots of tree allergens (which we suspected). Are these foods he should avoid? What exactly is the IgE measuring? When he was skin-tested, the only food that showed any reaction at all was walnut. Is that more accurate?

Thank you!

[Seawen]

More experienced moms can answer better than me but I think Class 2 means that there was some level of reaction found to those items and it's best to avoid to be safe. I think Class 0 means no reaction found.

[sbgrace]

They saw some reaction. You can have false positives (50% false positive skin and RAST/blood testing). Our allergist would do a food challenge for class 2 unless we had seen a reaction/were certain. They also do skin prick. If those foods were skin prick negatives I would think they are negative and the RAST numbers were false positives. False negatives are much more rare on those tests.

Did he have any other positive tree nuts? Do you have an epi pen? Tree nut and gluten free diet is a hard mix because there is rampant cross with tree nuts in gluten free foods and staples like flours. I wouldn't switch to that without reason and if you've never seen a reaction I'd assume not allergic.

[2rubies]

Thanks so much for your responses! We do carry an epipen everywhere- we have no doubt that he is anaphylactic to walnut. He was not blood tested for any tree nuts at all (I was told "they are not a common enough allergen"!!), but on the skin prick testing, cashew, sesame, almond, pecan, and coconut were all tested with no reaction at all. His walnut spot blew up like a balloon.

We are gluten-free now (we weren't at the time of the blood test), but that was mostly for me and my oldest. I think we've all seen some benefit from it, but it is very hard with the nut allergy now! Do think I should be avoiding his Class 2's (orange, tomato, peanut, and soy) even if they are negatives with skin prick testing?

Thank you!

[sbgrace]

No I don't. False negatives are unlikely and false positives are likely so those class 2 foods (unless you've seen reaction with consumption) are likely negative.

You're gluten free?

You've got to be very careful. He's got a decent (9%) chance of outgrowing a single tree nut allergy to walnut but almost no chance of outgrowing multiple tree nuts. If you're eating gluten free unless you're doing it very carefully you're exposing him to lots of tree nuts constantly. That's how my son became multiple tree nut anaphylactic. Rob's Red Mill flours and starches for example are produced directly with tree nut flours. That's just a start but almost everything we were eating was contaminated with tree nut.

I've got a list (though I'll have to find it) of tree nut free gluten free sources. I have to buy everything online as most of the time there is only one dedicated to a specific grain company that doesn't have tree nut contamination. The gluten free companies are a mess in that regard.

It's tough to do gluten free and tree nut free.

[2rubies]

Thanks Rachelle! I thought I was doing ok just to avoid walnut. I thought the cross-contamination with almond (which is what most of them seemed to be) would be ok. It never occurred to me that I could be making this worse for us in the future I bought some of the King Arthur flour blend (which is made in a dedicated nut-free facility), and although I loved it, I'll need a second job just to pay for it, I'm afraid!

I did try wheat again in an effort to make nut-free a little easier, and learned the hard way that I do really need to be gluten-free. This is exhausting!

[sbgrace]

I'd be afraid to feed an ana to one tree nut child other tree nuts because I believe our kids are statistically more likely to develop new tree nut allergies. So beyond cross I'd be concerned in your place.

You can do gluten free tree nut free though--we largely are though he's eating spelt once every four days in rotation.

I can give you a list if you'd like? I just need to either find it or make a list from the foods I use. I've got sources for most GF grains.

[lnitti]

Originally Posted by sbgrace

No I don't. False negatives are unlikely and false positives are likely so those class 2 foods (unless you've seen reaction with consumption) are likely negative.

my dd is class 2 with soy. Our allergist said to avoid it until she is older when we can do an oral challenge. Skin test for soy was also negative.

[sbgrace]

Originally Posted by lnitti

my dd is class 2 with soy. Our allergist said to avoid it until she is older when we can do an oral challenge. Skin test for soy was also negative.

Allergists may differ on advice. But generally if you've seen a reaction you would assume allergic even if testing is negative. If you've not seen a reaction and you get a positive on a test you'd be suspicious this is false positive given the 50% false positive rate. That's why, generally, testing a range of things without suspicion is a bad idea--you're likely to get some false positives. If your daughter seemed to be having soy reactions I'd avoid for sure. Our allergist does do oral food challenges for class 2 allergens in old enough kids if there is question about the allergy.