RAST or Skin Prick

Posted on: Tue, 10/19/1999 - 4:20am
Beth38's picture
Joined: 10/19/1999 - 09:00


Which is better ... the RAST or skin prick test? My son is 2 and has mild eczema (I've read that if eczema is present, the RAST is preferred). I don't prefer the RAST test for my son due to a bad experience with blood drawing a few months ago (but I'll go with it if that's what's required). I would be interested in knowing how other children responded to the skin prick testing and if there were any bad reactions to it, what to look out for, etc. Any information would be appreciated. Thanks!!

Posted on: Tue, 10/19/1999 - 4:36am
Christine's picture
Joined: 02/03/1999 - 09:00

I have only "heard" that the skin prick test is more reliable. My son demonstrates a 4+ on the skin prick test to peanut and egg. He also has a pretty severe case of eczema. We have never had a bad experience with the skin prick test besides the itching at the site of the reaction. Once the 15 minutes is up the allergist puts some Elocon cream on the welt and my son immediately feels better.

Posted on: Wed, 10/20/1999 - 9:50am
MaryLynn's picture
Joined: 06/25/1999 - 09:00

My daughter had a RAST an we feel that the results are very accurate. My allergist said that it is more common to come back with a false negative which if there is a history of problems would be followed with a specific skin prick. Since we were testing many different foods that were potentially life threatening I felt much safer with the RAST.
Mary Lynn

Posted on: Thu, 10/21/1999 - 4:18am
Donnamarie's picture
Joined: 11/16/1999 - 09:00

That depends on the severity of the allergies. Two years ago, our NEW allergist gave my son several skin prick tests (including peanut and mixed nuts). My son had an anaphylactic reaction, and the doctor came running in with the Epi-Pen. Thank God that worked... and it wasn't severe enough to go to the hospital. Now I NEVER allow my son to have skin prick tests on peanuts, nuts, or any other substance that I feel could be dangerous (although I did let them do it for dogs and cats and stuff). If your son's reaction is severe, go with the RAST. I know the blood test hurts, but it's better than the alternative. As far as reliability, I've heard different views... but it comes down to the fact that you have to have several different types of tests to know for sure. ONE IMPORTANT NOTE: my allergist pointed out that the MIXED NUT skin prick test includes PEANUTS. Good luck!

Posted on: Thu, 10/21/1999 - 4:19am
Donnamarie's picture
Joined: 11/16/1999 - 09:00

sorry to post twice!! Just wanted to clarify that I NEVER went back to the first allergist. I have a fantastic allergist now (and he's the one who told me about the mixed nut test).

Posted on: Mon, 11/01/1999 - 10:50am
LIZ IN NC's picture
Joined: 09/10/1999 - 09:00

I have had the skin prick testing done and the rast. I am severely peanut allergic and react even
to airborne particles (I have not yet had a reaction in which my blood pressure drops,but I react quite suddenly with laryngeal edema). With the skin testing, I had a 4+ peanut reaction among other things. I did need to take some Benadryl in the doc's office because I could feel my throat tighten slightly. However, this was a better test for me because with the rast, I showed no elevation of IgE! This might have given me a false sense of security if I had not had the skin test (and also a very harrowing experience with eating peanut butter crackers just prior to being diagnosed). My allergist was not surprized by this--he said that the rast is not as accurate as skin testing, but it is safer. Interestingly, my sister had the rast testing done and she showed elevated IgE with numerous foods and my sister can eat anything without any problem. She has no actual food allergies. Go figure.....Has any one else had a similar situation?

Posted on: Tue, 11/02/1999 - 6:09am
LouiseLarsen's picture
Joined: 06/07/1999 - 09:00

If you look at my post today, (nov. 2) titled "testing vrs. anaphylaxis" you'll notice I'm stuggling w/t the same kinds of issues.
My child had severe anaphylaxis at 15 mos. old, yet last week had a neg. skin prick test with NO reaction whatsoever.
(Her first rast test was done at 16 mos. and was with a "IgE count/score of 31336" to Peanuts.
Now a year later a skin prick test says virtually nothing!
They sent in another blood RAST test last week which came back today, Nov. 3.
Now her IgE Peanut blood RAST results came back a "973". Whatever that means...
I go into to speak with the allergist about it next week.
I'm VERY confused.
Any insights?
[This message has been edited by LouiseLarsen (edited November 04, 1999).]

Posted on: Tue, 11/16/1999 - 10:20am
evelyn's picture
Joined: 07/30/1999 - 09:00

Will someone tell me where I can find information about RAST testing. My son was diagnosed 5 years ago after a severe reaction and the allergist just gave him a skin prick test which was "severe" about a 2 inch welt. He reacts severely even to cross-contamination. Should I try to find a doctor to do a RAST test. Of course we follow strict avoidance already.

Posted on: Mon, 11/29/1999 - 10:26am
Beth38's picture
Joined: 10/19/1999 - 09:00

Hi everyone,
Thanks for replying to my original question! The allergist chose to go with a skin prick test, and I can tell you that my son only screamed for a second and then he was fine. I'm glad we didn't go with the RAST (this time). He did show an allergy to peanuts, and no other foods (only tested for 9 items). His wheal was about 3/4 to 1 inch across at the most, and his eczema went nuts (no pun intended). They gave him a dose of epi and Zyrtec and he was fine.
I noticed above that some individuals received a numerical scoring according to the reaction - it wasn't presented to us this way. Does the numerical scoring apply to skin testing as it would to a RAST? What's the scale? There's soooo much to learn!

Posted on: Wed, 01/12/2000 - 1:29am
rscollo2's picture
Joined: 11/11/1999 - 09:00

i am going to my sons allergist Tuesday for a skin prick on peanuts and another food that he had a severe reaction too. I'm very nervous even though he assured me that because the offending foods don't enter into his blood stream he will be fine. If this is true why did your son (donnamarie) have an anaphylactic reaction??? Did your doctor give you any explanation? How many other Members have had their children skin pricked with such a server reaction? Any info will be helpful

Posted on: Sun, 01/16/2000 - 12:07am
Beth V's picture
Joined: 01/15/2000 - 09:00

Hi! My son Alex had both RAST and skin testing. The results for the RAST is not back, but the skin testing came back positive for peanuts. The hive was maybe
1/4" to 1/2". No other symptoms- just
hives, which is why we were there. They
said it was a severe reaction. That doesn't
seem too severe compared to what I've just
read. We've had M&Ms without a problem and
eat in restaurants- so far so good. Also
eat turkey and roast beef from the Deli.
It's hard to know what to do!!! What a learning process.


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