Negative Blood test after positive skin test

I really don't have any advice or thoughts on this. I do know this happened to a friend's child and her allergist said since he has a positive skin test and reacts to peanuts, he is still allergic and avoid all peanuts and may contains.

I have the opposite thing going on with my dd. She has a high rast for almonds. It is 11. We don't know what her skin test is because they always group the tree nuts together when testing. She ate toffee last week with no problems (it was an accident. I didn't realize toffee had almonds in it and fed it to her. I only checked for may contains or contains at the bottom-- big lesson learned). Anyway, she ate it and had always eaten almonds with no problem. but once she tested postive in the rast, I pulled it from her list of safe foods.
Now, the dr is saying to go ahead and let her eat almonds!

Scares me though. At what point will she have a reaction??? I feel like it is inevitable since she has such a high rast and allergies to other nuts.

Anyway, seems it is not black and white when it comes to allergies.

Thanks for your comments. We have since had a food challenge in the drs office. DS was given an extremely small amount of peanut butter (not even enough to cover the head of a straight pin). It took 12 minutes for the hives and itching to appear around his mouth. He was given a dose of xyzol (Rx strength benedryl) and another hour wait to be sure no other symptoms appeared. We left with a new epipen Rx and continue avoidance.

As for the tree nuts, will your dr test for individual tree nuts. Mine did. Thankfully, no tree nut allergies.

Dianne and Linkay--I just posted 2 blogs on allergy testing here in the blog section.

Skin Prick and Blood tests have HIGH false positive rates. The only way to determine a true allergy is through history of reaction.

If a child has no reaction to food being eaten AND test results indicate an allergy--I would discuss a food challenge with your allergist.

If there is no history of reaction to a food--it should not be tested due to the high false positive rate.

Many people go to an allergist and don't know what food they reacted to. The allergist does a full allergen panel and each food shows up as positive. It if very rare to be truly allergic to 10+ items.

Eczema can cause false positive results on both skin prick (sensitive skin) and blood tests (causing high IGE levels).

Super high rast results (over 14-15) usually do indicate a potential allergy in the absence of a reaction.

However, under 14-15 and no reaction could mean a false positive.

Bottom line is--if your child can eat a food without reaction--he/she is probably not allergic.

As always--discuss with your allergist! :)