Community› The Bump Message Boards› Food Allergy
Food Allergy
New Discussion

RAST positive but exposure negative ?

wifeofadamwifeofadam member
in Food Allergy

My older son was at one time allergic to all of the following - cow's milk, goat's milk, eggs (white and yolk), peanuts, pineapple, soy, and tomato.  He has outgrown everything but the peanuts and milk at this point (he will be 4 in August).

A few weeks ago I realized he hadn't had a reaction to milk exposure in a long time.  In the past he would break out in a "fingerprint" rash if I touched him with butter on my fingers and stuff like that.  So I decided to test it out, touched him with butter - nothing.  Touched him again with milk - nothing. 

A week later I decided to do my own controlled food challenge (epi in hand) and give him a very tiny amount of cookie with butter in it and nothing happened.  We waited 15 minutes and he had another bite - nothing happened.  And so on.

At that point I decided to order up a RAST test to confirm things.  He had the RAST done on Monday and since then has had three or four items with butter in them without a reaction (in the past this exposure would have created hives in the least and major swelling/breathing issues at the worst).  Well, I just got the RAST results and his level was a 36.4 for milk. 

I know RASTs can have false positives and that the only true indicator of an allergy is exposure.  If he isn't reacting with exposure, would you assume it's a false positive?  I obviously don't plan to give him any more milk product until we meet with an allergist, but I just wanted to hear if anyone else has had similar experiences - positive RAST with negative when exposed to allergen.

Also, I am not recommending anyone else expose their child to allergens intentionally.  I do realize the risk in doing this. 

    
Report Reply to Post

Re: RAST positive but exposure negative ?

  • magdusiamagdusia member

    wow! that's awesome that he didn't react!!!!

    one of the things that my allergist told me that stuck with me (and i read it in a book also)... If we all took an allergy test (blood) we would possibly all have a positive to something but our bodies know how to handle it (it's possible that we will one day react to it though).  So just because it says it's positive, he can still tolerate it.

    I wish i remember where i read it but i think it was the book "pass the nuts" by slone. 

    Report Reply
  • Loading the player...
  • ABColeslawABColeslaw member
    Very possible that it was a false positive.  I'd just see what the allergist says.   And a blood test. 
    image
    Asher Benjamin and Lola Aisling

     Infertility
    PCOS, Progesterone Deficiency Disorder, Multiple Miscarriage
    Clomid, Metformin, Ovadril, PIO, P17 Iron/Platlet Tranfusion

    My Spring Babies! 
    <3 Angel Baby   Elisabeth Adelle  April 2008 <3
    Asher Benjamin  April 2010
    Lola Aisling  May 2014
    Report Reply
  • wifeofadamwifeofadam member

    imageABColeslaw:
    Very possible that it was a false positive.  I'd just see what the allergist says.   And a blood test. 

    The RAST is a blood test.

        
    Report Reply
  • macchiattomacchiatto member
    That's great that he didn't react!
    Our only exposure with RAST testing was when Will was tested for peanuts and eggs after testing positive on the skin tests for both. He tested negative for eggs on the RAST and exposure, and positive for peanuts on the RAST. We never fed him any and he didn't have any accidental exposure that we know of. At his followup one year later he tested negative for peanuts so we did a food challenge and he passed. We were thrilled but I do wonder if he would have reacted if he had eaten peanuts the previous year. It just seemed crazy he would completely ougrow it within a year. (He was 15m when he tested positive and roughly 27m when he passed the food challenge.)
    fraternal twin boys born january 2009
    Report Reply
This discussion has been closed.
Choose Another Board
Search Boards
"
"