Neg.caprast-then4+on skin test


My 2 1/2 year old daughter had a negative caprast for peanut in December and then last week had a skin prick test that was a 4+ (out of 4). For the skin prick test to be so significantly positive (after a Case 1 caprast one year ago and then the negative caprast last month) was very surprising to us. Naturally we are very disappointed. I feel like we are handling this stage of life very well with strict avoidance but the thought of going to Kindergarten in a couple of years is overwhelming. I saw a previous post about acidopholus (sp?) and am wondering if there is something to that theory. Audrey usually eats a ton of yogurt (with acidopholus) but she had not had any for several weeks before her SPT because I took her off dairy since she had some upper respitory stuff going on. Assuming that there was no longer a build-up of acidopholus in her system and then she had a significantly positive reaction just makes me wonder... Incidentally, she also received the SPT for milk and was a 1+. This did not surprise me since she has always been fine with yogurt and cheese but if she drinks a cup of milk the sinus type stuff kicks in later that day. I guess as long as she has no symptoms with yogurt and cheese we will continue those. If anyone has another opinion please feel free to share. Thanks for letting me share our results. I am so thankful for the support on this site!!!

On Jan 28, 2005

Taking a stab at this...

A negative SPT is about as good as you can get. There are hardly ever false negatives. But, the rate of false positives can be like 60%, especially in an allergic child. So if there are other allergies, the SPT could be positive even if she's not allergic. Also, I think I remember reading that a SPT can be positive even years after an allergy is outgrown. Bottom line for me is that I wouldn't put much stock in the SPT. I'd repeat the CAP RAST in a year or so and see how it looks.

On Jan 28, 2005

nopb4us - I'm so sorry to hear about your test must have been so disappointed, I would've been.

But, I agree with BENSMOM. When we had my ds tested for peanuts, they also tested him for eggs and he scored a 3+ on SPT for eggs..this was at 22 mos. He reacted at 9 mos to eggs and then we tried eggs again at 12mos (per our ped.) and he was fine. We continued to give him eggs and he ate them with no problem for almost a year! We stopped when we got his results, but the allergist says that the body has "memory" of the allergy for quite some time after the allergy is outgrown.

Your dd is still young and I would be optimistic, but I would definitely still practice strict avoidance.

------------------ Ree Mom to: Sean 3yrs - PA & EG Brian 1yr - MA

[This message has been edited by Ree (edited January 28, 2005).]

On Jan 28, 2005

RAST tests for specific IgE antibodies. If the food provoking those antibodies is removed from one's diet for an extended period of time, those antibodies can disappear. This doesn't mean one is no longer allergic. I think the positive SPT indicates that a *lot* of caution is necessary. Personally, I wouldn't risk reintroducing the food. A contact reaction like that is pretty nasty.

I've had negative SPT results for foods that sent me into anaphylactic reactions later that day/week. I've never had a false positive on a SPT result, but then again--I've never been tested for anything I didn't turn out to be allergic to. [img][/img]

My husband has had false positives and false negatives with SPT.

Also, serum used in SPT can go bad or be "incomplete". If one's skin isn't reactive or is overreactive, SPT is unrealiable.

Maybe after having had the SPT, another blood draw for RAST could be done? The exposure from the SPT might provoke enough antibodies to be measured on the test.


On Jan 29, 2005

OK, I bet this is not going to be much help, but myself personally - I would want the cap rast repeated, just to be sure. My son got a 4 on his skin test as well, but his cap rast indicated a class 5/6 allergy. Sorry. I can imagine how you feel. How frustrating [img][/img]

On Jan 29, 2005

I just don't understnad any of it....

My son has a 2mm reaction on SPT & a 45 IgE The Dr said he had a good change of out growing it when he did the SPT but he changed his mind after the RAST came back...

I just don't get any or it... Some people have low SPT & High RAST's other have low RAST & High SPT ??? Some people have neg SPT & Hight Rast's Others have neg. RAST & High SPT???

& none of us are gong to try to test it for real, thank god!

[This message has been edited by kkeene (edited January 29, 2005).]

On Jan 29, 2005

For what it's worth, my sons allergist said she won't even consider challenging for peanuts until his 5 or 6, and at that time in a hospital setting. Other allergens she'd consider, but not PA. Even if his CapRast and SPT came back negative, she doesn't see the need to challenge him until he's ready for school.

Also, my ds CapRast was tested wrong last year. His allergist called and said that he came back negative...then 2 minutes later she said "oh no, they tested for IGG not IGE...this information means nothing to us and we'll have to repeat the test." After the 2nd test, he came back 1.7/Class 2. I think I'll request a 2nd test if he ever truly comes back negative...

[This message has been edited by Ree (edited January 29, 2005).]

On Jan 29, 2005

Thanks, everyone, for your suggestions and support! It really helps to know we are not alone in this! Our allergist does not plan to do another caprast until my daughter is 5. However, if our pediatrician does any blood work at her 3 or 4 year check ups then I am going to see if he will order a caprast for peanut too.

On Jan 30, 2005

We had the same situation with dd as Ree. She reacted to egg at 9 months (vomiting). I took her off for about a year, then she ate eggs with no problem until age two, at which time she had a positive SPT for peanut and egg. We avoided egg completely until her CAP RAST came back. The number was low enough for the allergist to do a food challenge. She passed with no problem and now is eating eggs again with no trouble.

We were also told that she was allergic at one time, but had outgrown it and was still just testing positive on the skin test because of that.

Shannon McKenna-Kate 2 1/2, PA

On Jan 30, 2005

Shannon, do you mind me asking what Kate's CapRast to egg was? Sean's was higher than his peanut, so they haven't challenged him. They said they would this summer before preschool (egg only). His last CapRast was Egg 3.8 and Peanut 1.7. The egg didn't move at all after 1 year of avoidance, but the peanut dropped almost in half. It's just so weird b/c he never reacted after 12 mos...he didn't like eggs, but he ate Eggos almost everyday for a year!

Just curious...Thanks! Ree

------------------ Ree Mom to: Sean 3yrs - PA & EG Brian 1yr - MA