My son's skin test wheal size decreased from 10mm to 4mm but his cap rast increased from 18 to 38. He has never been exposed to peanuts (another allergy led to allergy testing). Does anyone know why one test would decrease and the other increase?

It's more or less how they test. With a RAST test, I don't think they introduce histamine. I mean, I don't know. It's the reason why when I reflect on things, I think my allergist was a nutcase because I had a lot of skin test welts that itched and all he came back with is that I was borderline allergic to timothy grasses. However, I am now on allergy shots by my ENT for the grasses only to find out that there's no such thing as borderline.

I think if you ask the doctor that did the testing, he should be able to tell you though because it does seem a little unusual.

Allergy testing is a great thing but unfortunately there is not always an answer to these types of questions.

Every food allergic child is different and will react differently to testing. There are so many variables to consider that can affect testing....such as...

If your child has recently had a reaction or has been sick and has a weakened immune system.

If your child has sensitive skin or eczema (in the instance of skin prick testing)

Some children start to outgrow their allergies and will still have a pos skin prick but negative blood test.

Some children will no longer be allergic but still have a pos blood result.

My son has pos results to skin prick and blood for soy and can eat soy fine.

The only true way to know an allergy is by history of reaction or by food challenge in combination with testing.

As the previous poster suggested - you should consult with your allergist.

Hope that helps!
Ruth

ses- is your allergist an immunologist as well (some are) You can always ask regardless for immunity testing.
I didn't know what this was, Corey just kept getting sicker and sicker last year, and we kept changing and increasing medicines with all his specialists. Our allergist ran an immunity test, and his levels were extremely low, which just shocked me, b/c I didn't expect it. We were able to get a shot, then a booster to follow, and he will rerun in December.
If I were you, start with the allergist and ask questions. I will check in if I come across any information for you.
Good Luck.

-Gina

My daughters #'s increased with out any reactions as well. I have found that I was feeding her many things I was not totally sure of. She went from a level 1 to a level 4 over 3 or 4 yrs. I then became much more careful about what I fed her> We stopped eating out and started using philly swirl for our icecream, and if I wasn't sure she didn't eat it. In one year her numbers went from a 21 to a 10. Now thats some drop. If it means staying this strict to get her to outgrow it I will. She also had a negative skin test on several occasions, so be careful.