Diagnosed as anaphylactic by testing with no exposure....

[daisy madness]

Not necessarily on here, but every so often I see an online comment like "DD is anaphylactic to tree nuts and milk, but has never been exposed."  Are they getting this anaphylactic diagnosis from testing?  I thought the testing (aside from a food challenge) can't predict the severity of a reaction that a person may have. Is there a test that shows severity? 

[CMdeux]

The answer used to be an unqualified "Nope-- no way to know without finding out the hard way."

Then the answer was; "Well, shellfish and nut allergies TEND to be anaphylactic."  THEN the answer was; "No testing without an unexplained or probable reaction," and finally we are to a place where component testing has made it POSSIBLE to identify (somewhat) just who is at risk of anaphylaxis from a peanut sensitization.

That is, some protein subtypes (Ara h2 in particular) are associated quite strongly with anaphylactic responses.

On the other hand, I'm not sure just HOW low the false-negative rate is for those who aren't clinically allergic, but are sensitized and possess protein-specific IgE.  KWIM?  It's likely that at least a few of those people are in that group.  But the only way to find out is, you guessed it-- the hard way. 

A child with a peanut IgE >20 who tests positive for Ara h2 sensitization is probably a REALLY bad risk for an IOFC, regardless of history, unless that history involves eating the allergen on a regular basis without ill effects.  Even then, many clinicians would want to do it in a hospital.

[hedgehog]

DS recently tested as not being likely fir anaphylaxis.  However, he has had one anaphylactic reaction.  The question is whether the desensitization has caused that test result.  Possible, but they don't know at this point.  But the doctor did find it very interesting.

[daisy madness]

Thanks for the explanation.  I'll be sure to ask the allergist about it at our next appointment.

[YouKnowWho]

Ds2 has had no exposure to peanuts that we know of short of having hives when he stuck his arm in a bin of raw peanuts.  But he has highly reactive skin.  He honestly should have never been tested for PA but our oh so helpful allergist through the test in for her personal enjoyment (he was reacting to other foods and I think she got a sick sort of enjoyment on diagnosing my kids allergic to everything just to see me cry).

DS2's numbers are too high to challenge in the office without having the FAHF2 test done.  It was not covered with previous insurance but we had planned to do this year regardless.  I just can't get him to quit random hiving to make a trip downtown to the allergist worthwhile (hives are from random temp changes, not helpful this summer with the weather being bi-polar). 

It's not as a big deal to me having had a few years of allergy management under my belt.  I also have a very relaxed way of doing things for him as opposed to DS1 who has a definitive ana history to wheat, barley and egg (and while he has never reacted to rye, it's a class 6 and likely).  I read labels, I do not call.  We avoid may contains and shared lines, not worried about shared facilities for the most part.   I take chances with him that I would never take with DS1.  Having said that, I always have epis on hand.