Anyone knowledgeable re: food allergy testing?

[Logan Sapphire]

I can't seem to get any good answers and I'm finding myself more and more confused. My son, almost 4, has a peanut allergy. He has had mild reactions from eating and being touched by peanuts, though it's possible he's had two vomiting reactions but we don't know exactly what caused that.

He has only ever been skin tested. The first time, he had a large peanut wheal and a mild pecan one, so we avoided all treenuts as well. The second skin test showed a more moderate peanut wheal and no reaction at all to any treenuts (well, at least the common ones that were tested). The allergist said either the pecan reaction was a false positive or he outgrew it since it was so mild.

His third appt is coming up next week. Our allergist only does skin testing for peanut allergies, though I read the exact opposite- that the blood test (RAST) is more reliable. My husband is very opposed to testing DS again, as he feels that we'll have to put him through the awfulness of the skin pricks only to show that the peanut allergy is still there. And then that raises the other question- do we have him tested again for treenuts, even though the last test showed no allergies? Or do we skip it but continue to avoid treenuts out of prudence due to cross contamination with peanuts?

I wish someone could tell me definitively whether RAST or skin testing is better? I know the gold standard is having had a reaction, which he's had, but still...

 

[chrono]

LS,
I have no experience with skin testing for food allergies. It works great for contact allergies but I don't know how accurate it is for ingestion type allergies and I don't know whether it makes any difference between contact and ingestion. With my son, determining his dairy allergy was easy and obvious to the point where having testing done was clearly unnecessary. He broke out immediately in giant hives all over his body and face at the slightest amount. Thankfully, he has outgrown it. He took the prick test for other allergens and he is now taking shots for seasonal and animal dander allergies.

 

[baby monster]

DS has a reaction to soy and peanuts. He does eat all other tree nuts with no issues. I only go by reaction as all of the testing is riddled with either false positives or false negatives. My niece has severe allergies to several foods but all testing has been inconclusive. At the same time, if she eats anything with certain foods, she'll break out in hives and have severe intestinal reaction.

 

[ChristineRose]

This guy knows a lot about it, and is highly regarded.

http://www.quackwatch.com/01QuackeryRelatedTopics/Tests/allergytests.html

The site was an MD's retirement project and it doesn't update often so it may be a little out of date. But I think it answers the question: RAST is the least useful diagnostic but protects your child from the possibility of a reaction.

 

[amc80]

We had B skin tested at 12 months due to constant congestion. He tested as allergic to dairy, and sensitive to soy, eggs, and peanuts (and allergic to cats on the environmental side). His allergist suspects that he's not really sensitive to those things and his system was just amped up from the cat and dairy. Just to be careful, he wants us to wait until B is 2.5 to introduce peanuts, and he wants us to do it in his office.

I guess that isn't answering your question as much as sharing my experience. I have heard the blood tests aren't as accurate.

 

[marym]

Not sure which method is better, but FWIW, when my daughter was a year old they did the skin prick test (which was pretty unpleasant for her) which confirmed her egg allergy. The following year when it came time for her to be retested, I requested a different Dr in the practice, as I didn't much care for the first doctor we saw. The new doctor didn't even bother to do the skin prick test again and just went straight to the blood testing. I didn't question his decision, as he is a very reputable allergist in our area.

 

[MichelleCarmen]

Hi,

If I were you, I'd avoid tree nuts due to cross contamination regardless if you test or not. That said, I had food allergy blood tests. One was the immediate and the other was the delayed response allergy test (ELISA) about five years ago and it said I was allergic to eggs and dairy. I know those are correct especially since I quit having headaches after I stopped eating eggs. But, still, I have a feeling the test wasn't 100% accurate because sometimes I'll eat foods that the tests said I'm not allergic to and will get an itchy nose or have an all-over itchy sensation on my skin. Since these aren't life-threatening allergies, I don't have to worry...but, if they were life-threatening, it's scary to know the tests didn't figure out these reactions.

But, either way, if you do get the blood testing, the tests aren't too expensive. My two tests were $220 (my insurance didn't cover them), so for me it was worth it to know for sure about other foods, however, I believe my elimination diet was more accurate (I cut out most foods for 6 weeks).

 

[marcy]

I had both the skin tests and blood tests and the skin tests appeared to give me more accurate results. Good luck with finding what foods your son should avoid.

 

[Munchkin]

RAST testing is less accurate than skin prick or oral challenge but it is safer because there is no risk for reaction. That's why RAST testing is often done with potentially anaphylactic allergens but not usually with environmental-type allergens. There are definitely many false positive RAST results out there.

Are you sure your allergist even wants to do tests at the next appointment? I only have new tests done now when I think I have developed a new allergy. Usually my allergists sees me a few times a year in follow up, write new EpiPen scripts, etc.

 

[perry]

I personally did the IgG ELISA "Immuno 1 Bloodprint" by Immuno Laboratories in Fort Lauderdale, Florida, with all the accessory testing in 2002. It found virtually all of my various food allergies and quickly substantially changed my life. Skin testing did not identify a fraction of what turned out to be very real problems for me. Here is the link

http://www.immunolabs.com/


Immuno Labs does tell you that only food avoidance can confirm if you have problems or not. Also, that many "issues" do go away with time and often foods can be reintroduced. I see they currently list a 100% money back guarantee if your clinical condition does not improve based on the results of the test.

In my case I paid for the testing up front (and my Dr had the blood draw done at the Dr office); and insurance later reimbursed me for about 1/2 my cost of the testing. But, this was most definitely worth it for me.

While I see some value in skin testing. For me this specific test provided the key answers for my food allergy issues.

I hope things work out well for you,

Perry

 

[Logan Sapphire]

Thanks, everyone.

We definitely will continue to avoid direct consumption of treenuts regardless of whether he's allergic or not, due to the cross contamination with peanuts. If he continues to not be allergic to tn, though, I might be more lenient with things like "made in the same facility with almonds" since he wasn't allergic to almonds to begin with. Never made on the same equipment with treenuts, though.

He's being tested; our allergist likes to test yearly and unfortunately, I screwed it up by giving him Zyrtec the past few days and had to reschedule his testing from this past Tues to next Monday. I think he might've said that depending on the skin test, he might order a blood test and then depending on those results, we could consider a food challenge, which would scare me. I'm hoping against all hope that he's one of the lucky ones who outgrows this allergy, but I know the odds are against him (though he may well have outgrown his pecan allergy, so who knows?).

ETA: this is from his last test. The peanut wheal is lower left quadrant. It's not large but I don't know if that means he's "less" allergic than when it was a much larger wheal. The rest of the pricks are treenuts and environmental, as well as the histamine wheal.

 

[MichelleCarmen]

ETA: this is from his last test. The peanut wheal is lower left quadrant. It's not large but I don't know if that means he's "less" allergic than when it was a much larger wheal. The rest of the pricks are treenuts and environmental, as well as the histamine wheal.

Ouch! Hope you guys figure out all his allergies and he finds a nice group of foods he can enjoy!