Are allergy tests accurate for delayed reactions?

[DevaMajka]

I have an appointment with an allergist in a month. Most of my reactions thus far seem to be delayed by a few hours (I don't know what I'm reacting to, but it's not been directly after eating anything). Will an allergy test be reliable for delayed reactions?

Also, do they test for chemicals, such as in body products? or is it just food, dust, pollen, etc?

[mamafish9]

There are tests for food intolerances (that's technically what a delayed reaction is, vs. a true "allergy"). ELISA and ALCAT are two of them. Most allergists don't believe in "intolerances", but if you find one that does, it would be a different set of tests than the standard allergy tests. (Standard allergy tests look for IgE antibodies, intolerance tests for IgG antibodies).

[DevaMajka]

oh, hmmm...I thought there could be delayed IgE reactions. (that's the real allergies, right?)
I don't know much about allergies! lol.

If delayed reactions aren't really allergies, and can't be dealt with by an allergist, why would the doctor send me to one? I told him it happened later in the day, after I ate the potential triggers. grrr...

Wait...thinking about it more, I'm more confused. My reaction to mango was called an "allergy" at the hospital, and I've been told that facial/neck swelling and hives would be due to a real allergy, and not an intolerance. That reaction happened about 5 or 6 hours after I ate the mango.

Can facial swelling and hives be due to intolerances? And could intolerance symptoms be treated with anti-histamines (they gave me iv anti-histamines, iirc. It was many years ago)?

[changingseasons]

I think IgE can be delayed a few hours, although they usually have more immediate symptoms. But yes- hives and swelling definitely sound like IgE ("true" allergy.)

[DevaMajka]

I should add that the hives and swelling were from the mango years ago. My recent reactions were rashes and very mild facial swelling/puffiness. So maybe this time it is an intolerance rather than an allergy.

I hope it's not pointless to go to the allergist! At least insurance covers it.

[kjbrown92]

When I took DD2 to an environmental doctor/allergist a few years ago, they did intradermal testing (where they actually inject the allergen under the skin in 3 graduated doses vs. scratch testing). DD2 reacted to one of the things a day later, and it stayed red for more than a week. The doctor said that was considered an allergy. However, that doctor's son, who is a naturopath, in the next office... my SIL went to him, and he did the exact same kind of testing on her, and he said if things came up the next day, it was an intolerance.... Personally, since I think they're two different mechanisms, I would say if you react to skin testing like that it's an IgE response (either immediate or delayed), but that's just my opinion. And I also think if it reacts to an antihistamine it's an IgE response. I could be wrong though!

[DevaMajka]

Thanks for sharing that your son and sil reacted a day later. At least I know that's a possibility, so the appt might not be pointless!

Originally Posted by kjbrown92

And I also think if it reacts to an antihistamine
it's an IgE response. I could be wrong though!

I was wondering about that, too.