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Posted on: Tue, 09/19/2006 - 11:28pm
mommyofmatt's picture
Joined: 03/12/2004 - 09:00

We're testing my ds (no known food allergies) throuh a GI at this point.
He seems to have food sensitivites which aggravate his reflux. Unfortunately, we're doing an endoscopy to look for any IGA mediated allergies (among other things)that do not show up on traditional allergy tests of RASTS and skin. His traditional tests were all negative.
From what I've read so far, if an allergic reaction is a delayed one, it could be IGA mediated, and would not show up through traditional testing. Some people also seem to do patch testing where the allergen is placed on skin and then taped over and left there for a few days to see if there's reaction.
I'm just sort of beginning my research in this fun-filled new area for me, so hopefully what I'm saying is correct. Feel free to jump in anyone if I've got this wrong...just thought I'd mention it in case it's something you want to look into.
Good luck! Meg
[This message has been edited by mommyofmatt (edited September 20, 2006).]

Posted on: Wed, 09/20/2006 - 12:17am
Greenlady's picture
Joined: 06/30/2004 - 09:00

Thanks for sharing your experiences - it's one of the best things about these boards.
I remember reading in a transcript of Dr. Robert Woods' presentation to the FDA about "non-IgE mediated food allergies", which might just be another term for intolerances, but it sounded a lot like the symptoms you were describing. I'll see if I can find his discussion and post it here.

Posted on: Wed, 09/20/2006 - 12:42am
Greenlady's picture
Joined: 06/30/2004 - 09:00

From Dr. Woods' lecture (page 34 - 41). Not much practical help, but it may give some more background and terms to search on:
DR. WOOD: Now, the last category that I want to mention is something that we will lump together as gastrointestinal food hypersensitivity.
There are a variety of conditions that fall under this umbrella.
There are some that are in the immediate
hypersensitivity category. This would be part, say, of an anaphylactic reaction where someone ate food, broke out in hives, had vomiting, diarrhea, abdominal pain, or other gastrointestinal symptoms.
There is another condition called "oral
allergy syndrome" where patients have reactions that are confined to their mouth or throat or lips, particularly related to fresh fruits and vegetables.
There is another group of conditions that
are lumped under a category of eosinophilic disorders of the GI tract. There is a specific condition, eosinophilic esophagitis, where only the esophagus is involved. As most people in the audience know, the eosinophil is a type of white blood cell that is most affiliated with allergic reactions.
If you take someone who is having a bad hay fever day outside today and look at their nasal secretions, their nasal secretions will be loaded with eosinophils. If you take someone that is having difficult asthma, their bronchial mucosa will be loaded with eosinophils.
By the same token, if you have allergic eosinophilic esophagitis, the lining of your
esophagus is loaded with eosinophils. It may be isolated to the stomach, it may be more diffuse where we would call it "allergic eosinophilic gastroenteritis." This is somebody who may have disease anywhere in their GI tract, and oftentimes very diffusely.
There are some other conditions, enterocolitis syndrome and dietary protein
proctitis, that are much more common in very young babies.
The importance of presenting these different syndromes here is that some of these syndromes are IgE mediated and some of them are not IgE mediated, some of them are very acute and some of them are very chronic.
It turns out that those syndromes that are more chronic and low-grade that don't present with any acute symptoms, don't present with any clear cause and effect of eating the food and having increased gastrointestinal symptoms are going to be, potentially, the most difficult for this Committee to grasp. That is because these patients are often reacting to remarkably small exposures.
I will come back at the end to sort of
give a couple of examples of the dilemma that kind of patient is going to present to us as we really try to figure out what is safe and what is not safe.
It also turns out in the same vein that the non-IgE conditions in general are probably going to be most difficult to deal with, both because they often don't have the acute IgE-type symptoms, and because they are predominantly mediated by a different part of your immune system that can recognize even smaller degrees of these food proteins that identifying thresholds are going to be much more difficult.
DR. WOOD: Now, when we are trying to approach a patient with a food allergy, one of the real difficulties is making an accurate diagnosis.
The diagnosis, as in most everything we do, begins with a history, talking about the foods they suspect are causing problems, whether we think the symptoms are consistent with food allergy, whether
this is something that may not be food allergy at all, or whether it may be a food intolerance rather than an allergy. We are going to be interested in the timing of the symptoms and the reproducibility of reactions.
It turns out that when you do a very careful history, most of the time it is wrong. It will be correct in the acute reactions, where you have a patient who comes in and says, "I fed him scrambled had hives all over." "She took her first bite of peanut butter, and developed hives within 2 minutes."
It is very likely that the history will be
born out when you do further testing. However, when you look at the bulk of patients with food allergies, many of them will have these more chronic conditions like eczema or the gastrointestinal disorders. When you are looking at those patients, you will only verify the history when you do further testing about a third of the time.
DR. WOOD: The next set of tests we do after taking a history would typically either be skin testing or serologic testing. A RAST test, "radioallergosorbent test," is the most common serologic test that is used.
These tests have some value and they also have some problems. The problems they have is that there is a relatively high rate of false-positive tests. They do not have a terribly good positivepredictive accuracy.
They are generally accurate when they are
negative. Although, they will only be active when they are negative when you are convinced this patient has an IgE-mediated condition, because both of these tests rely on the presence of IgE antibodies to identify the specific food allergy.
An example would be if a patient develops
hives or anaphylaxis, which typically are
IgE-mediated, and they suspect that it is a certain food. If you get a positive test back, it is verylikely that they have that allergy. If you get a negative test back, then you need to keep looking.
It was not likely that food that caused that
However, if you have a patient with something like the allergic eosinophilic gastroenteritis where there may not always be IgE antibodies, you cannot stop with a negative test and say, "We've proven you don't have food allergy." That is something that happens all the time, but it is often going to lead to a misdiagnosis and mismanagement of that patient.
The bottom line is that we need to carefully interpret our tests in the context of the overall clinical picture, and that we need to rely on oral challenge tests as the more accurate tests, so that we will say that they are not completely definitive. They are more definitive but not completely definitive.
Again, they are going to be less definitive in the patients that have more delayed type reactions or more chronic conditions where they won't react in that four-hour observation period of your food challenge.
Here's the link to the whole transcript:

Posted on: Wed, 09/20/2006 - 11:13am
anonymous's picture
Joined: 05/28/2009 - 16:42

Greenlady and Meg -
Thank you!! [img]http://uumor.pair.com/nutalle2/peanutallergy/smile.gif[/img]

Posted on: Tue, 10/17/2006 - 11:18am
anonymous's picture
Joined: 05/28/2009 - 16:42

Just bringing this up to date.
Our son's RAST results are in : all negative for the things he has GI reactions to.
We're not dismissing this outright - we still plan to monitor our son's consumption of these foods closely.
It sounds to me like it could very well be what you posted about Greenlady.

Posted on: Tue, 10/24/2006 - 12:24am
caryn's picture
Joined: 11/20/2002 - 09:00

I know my son has trouble with various items also and we lump them all together and rotate the whole lot -- so if he has trouble with cinnamon and food dyes -- then we try not to ever give him both in the same day and hopefully not even every other day -- so not just a little cinnamon at breakfast and a little blue dye at lunch -- maybe a little cinnamon at breakfast on saturday and a little blue dye at lunch on monday... though we are not the greatest at this and i know we don't know all the things that irritate him.
it is a process of elimination to narrow down the culprits.


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