HELP! Re: test results

2 replies [Last post]
Mon, 08/08/2005 - 15:35
jessyandsophiesmama
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User offline. Last seen 3 years 17 weeks ago. Offline
Joined: 06/13/2005

My son tested positive on the RAST test to peanuts at 11 months. He tested a class 2. We did another RAST at 17 months old to check on his lowering egg allergy. Peanut at this time was completely, 100% negative. He had an oral challenge to egg and peanut in June. He passed egg and failed peanut. He got hives from head to toe.
Just last week, at 18 months, he had another RAST, he reacted to cinnamon... we had them add Peanut. It still showed negative. Today he saw the allergist and even though I KNOW he is allergic, since he failed the oral challenge, I had him skin prick him anyway, it was VERY positive.. showing a class 3 allergy.
Why all the negative RASTS? His egg was always positive, along with skin testing. Does this mean his allergy isnt as severe?? I guess this confuses me.
Thanks for any thoughts.
Sarah
Jessy 18 months

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Mon, 08/08/2005 - 16:41
#1
starlight
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User offline. Last seen 3 years 17 weeks ago. Offline
Joined: 01/16/2004

My family doc told me that RAST tests test for IgE response, whereas food allergies involve IgA responses. So they're not always going to be accurate.

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Tue, 08/09/2005 - 03:42
#2
mommyofmatt
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User offline. Last seen 3 years 17 weeks ago. Offline
Joined: 03/12/2004

From all I've heard/read, the "true" indicator of an allergy is reaction. If they've reacted, they're allergic. As far as severity goes, with PA in particular, it can be very unpredictable. A mild reaction one time can be anaphylactic the next. I wouldn't pay too much attention to the RAST since he's reacted and was positive on the skin test.

RAST tests do produce false negatives. My ds (I feel like I told you this already, sorry if I did!) had a negative RAST to milk, but positive skin. We did a challenge and he failed at 1 part milk to 100 parts water. The allergist simply said, he's still allergic, avoid for another year.

Sorry if this wasn't what you were hoping to hear... Maybe he's got a chance to outgrow though since the RAST is negative? I don't know. If I were you, I'd keep avoiding everything peanut, and still carry that epi everywhere. Meg

__________________

***[b] ALLERGY ELIMINATOR*** [/b]

Meg, mom to
Matt 3 yrs. PA,MA,EA
Sean 3 yrs. NKA

__________________

***[b] ALLERGY ELIMINATOR*** [/b]

Meg, mom to
Matt 3 yrs. PA,MA,EA
Sean 3 yrs. NKA

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