This is probably not what you want your child's doctor to say to you. At least it isn't what I'd been hoping to hear when I took Matthew to his allergist appointment last week.
Here's what happened:
The middle of October, Matthew had a couple of vials of blood taken to do some testing on. However, instead of doing the full array of food allergen testing that they were supposed to do, they only tested a few things (milk including a few sub components, egg and peanut). I was pretty frustrated--I'd thought we were testing for a bunch of allergens and wanted to see how the results differed from January's test--were there new allergens, how had his known allergen values changed, etc. Plus why had they taken 2 vials of blood for so few tests? That's a lot of blood from a little boy! Anyhow, the nurse practitioner suggested we could do some skin testing to get some additional information. Not ideal, but hey, it's something. So we did. We tested whole egg, egg white, egg yolk, milk (not expecting it to be positive since it wasn't in April), fish and soy plus a positive and negative control. The results were baffling. He reacted a lot to the whole egg. However, there was just a little reaction to egg white and egg yolk. Yeah, so what part of the egg is he allergic too??? In fact, his reaction to them was smaller than his negative control (which should not have had a reaction at all) which kind of made all the results suspect. They retested the negative control on his forearm and it was completely negative. However, the fact that he reacted positively to it on the back means, um, something....maybe that he has sensitive skin? Maybe that the tests aren't 100% accurate (already known!). Baffling! So this is what the doctor said we had a conundrum about (egg results not consistent, 1st negative control was positive). He then proceeded to tell me that the most accurate indicator of if he's allergic is if he has a reaction to it when exposed. Example: if he gets hives on his face when exposed to eggs, he's allergic to them. Brilliant, huh? Clearly this is why we are going to the allergist :)
Here's a summary of the results:
Peanut: Blood test still showed allergy although blood level of IgE has decreased. Still considered class 2. We didn't do a skin test on this because we'd still completely avoid peanuts (and tree nuts) regardless of the results.
Milk: Blood test from April showed lower IgE level, although still a class 2. Subcomponent results in April were all class 1. Blood test from October showed a still lower IgE level--now a class 1. Subcomponent results were all lower than the threshhold value (class 0). Skin test was negative as expected. They told me that when the subcomponent values are 0, that usually means they can tolerate milk in baked goods. So we may started doing some of that, although we don't need to rush. However, I'm really glad we didn't do that in April when they told me we could since his subcomponent values then were not class 0!
Soy: No blood test done in October which is unfortunate. He had a large reaction on the skin test, probably similar in size to the whole egg reaction. We plan to continue what we've been doing with soy: small amounts in soybean oil or soy lecitin are ok, but not soy protein.
Fish: No blood test. Fish mix on skin test was slightly positive. Will continue to avoid.
Egg: Blood test results in October were negative (class 0). Confusing skin test results since whole egg was super reactive while egg white and egg yolk had little reaction. Plan is similar to milk: use egg in some based goods and see how he reacts. I should note that for baked goods, I mean things like bread or cookies that bake for awhile at a pretty high temperature as opposed to pancakes that don't bake very long. I suppose if he does ok on the bread, we could try the pancakes. However, I'm a bit reluctant to do that since the last time he had pancakes made with eggs, he threw up.
The skin test results are definitely weird. I've always known the tests weren't 100% accurate and Matthew demonstrated this in April when he didn't react to milk even though we knew he was allergic. The egg results are very bizarre, though. As is the fact that the negative control was positive. The nurse practitioner and I were discussing things we could do to try to unravel this mess the next time we do skin testing. I basically have his back all divided up to test his reaction to the positive and negative controls in different places. There probably won't be any room left to test for allergens :) (Design of experiments on child--must be an engineer.) But really, I wonder if the top of his back is more reactive. That's where the largest reactions have always been, although his milk has been on his upper back both times as well and that has had no reaction. So it's all very confusing. And I definitely am a bit skeptical of the skin test results whether they are positive or negative. I guess we'll just go with the plan and see what happens.
