With classical food allergies, the kind that show up in IgE RAST testing, the old model is that you just avoid the food. But gradual desensitization by taking tiny amounts of the food, has been shown to be promising in research. See for example http://www.medscape.com/viewarticle/711404_6
So could desensitization work for delayed food allergies, of the kind that might be an IgE-mediated reaction localized in the gut, but don't show up on skin or blood allergy tests?
Many people with delayed food allergies just avoid the food. That isn't too bad if you only have one or two food allergies, although people may get hypersensitive to an allergen when they strictly avoid it. But when you have many delayed food allergies, avoidance turns into something that causes a huge amount of trouble, and you may be left with too few foods to have a reasonably good diet.
Allergists talk about "cyclic food allergies" that develop from eating too much of a food. These allergies don't show up on conventional skin or blood allergy testing. But these cyclic food allergies are said to go away after a few months if you don't eat the food. For that kind of food allergy, avoidance probably makes sense.
But what if, like me, you have delayed food allergies that don't go away after a few months of not eating the food? Mine have lasted for many years.
It may be that strictly eliminating foods one is allergic to, is actually bad for one's immune system. The immune system develops tolerance for allergens, mostly via the GI tract from what I've heard. Lots and lots of foreign proteins come into the GI tract, and the body has mechanisms for developing tolerance to these proteins. These mechanisms work by being exposed to the food – not by avoiding it!
Also, I read that inhalant allergies are thought to be regulated via the GI tract, because some of the allergens you inhale, end up in the GI tract. So avoiding the foods one is allergic to completely, may interfere with the body "learning" to develop tolerance to allergens. Eating tiny quantities might train one's body to develop tolerance. Perhaps one should keep on eating foods one is allergic to, in small enough quantities not to cause a reaction.
I found that taking oral cromolyn, Singulair and 15 mg loratadine beforehand, makes my food reactions much more mild. Using those medications, I can consume a tiny amount of the food without getting too sick. So that's what I'm trying.
I have “rotated” most of my foods for about 10 years. What this means is that if I eat a food on one day, I don't eat that food again, or anything related to it, until 4 days later. This helps me avoid developing allergies to those foods as well. When I haven't rotated foods, I have sometimes developed new delayed food allergies, even if I only consume small amounts every day. For example, I developed a ginkgo biloba allergy from taking a ginkgo supplement every day.
So, I'm trying eating tiny amounts of foods that I've developed an allergy to, after taking oral cromolyn, Singulair and loratadine. I'm eating a given food only once every 4 days. Since this clearly helps in maintaining tolerance to foods, it may help in building tolerance as well.
For a long time, "delayed food allergies" have been thought to be very different from "true food allergies". People have described "delayed food allergies" as non-IgE mediated, or even as "food intolerances", meaning the mechanism does not involve the immune system. In some cases this is true.
However, at least for me, it's looking more like these allergies may be rather similar to "true food allergies" – and thus, the way of coping with them may be similar, too. Some researchers are coming to think this, also. IgE-mediated allergic reactions involve an immediate reaction, when the mast cells degranulate and release histamine etc. But they also involve a late phase, when other parts of the immune system become involved. So some "delayed food allergies" might be "true food allergies" with a mild early phase that doesn't show up in conventional allergy testing – but an intense late phase reaction.
My delayed food allergies start making me feel sick about half an hour after eating the food. That is actually consistent with IgE-mediated allergy, and not very consistent with a cell-mediated reaction. Cell-mediated reactions usually start about 24 hrs after eating the food.
Also, because the mast cell stabilizer cromolyn helps prevent my food reactions, they probably do start with mast cells degranulating- just like "true food allergies".
It's been found that mast cells can be degranulated in an antigen-specific way by immunoglobulin free light chains. See http://dspace.library.uu.nl/bitstream/handle/1874/221010/groot-korm... FLC's provide a non-IgE mediated allergic reaction that involves mast cells.
So some "delayed food allergies" may be mediated primarily by FLC's. FLC's may also be involved in inhalant allergies.
Some more info on what's going on with me: I probably have celiac disease, an autoimmune disease triggered by eating gluten. I'm not thinking of reintroducing gluten, because it can trigger an autoimmune process. I went gluten-free in 2003. I have many inhalant allergies that have shown up on skin and blood tests. I found out about my "delayed food allergies" by a series of elimination diets followed by food challenges.
As I've said before, I went through a kind of revolution starting in 2003, when I found I had been severely affected both psychologically and physically by food allergies. The allergies caused psychological hypersensitivity, LOTS of anxiety and depression, etc. Physically, they caused various inflammatory effects.
It was a very dramatic change for me when I stopped eating those foods – the physical symptoms went away and I felt like a different person, psychologically.
However, over years I found I had allergies to almost every food I had been eating more than occasionally. I hardly have anything left to eat! And none of my allergies have gone away.
My food reactions start about 1/2 hr after eating the food and last about 4 days. Mostly, it's a groggy sick feeling, but I've also had belly pain, back pain, frequent urination, joint pain, mild itchiness all over my body, and psychological symptoms like anxiety, tension, being more emotionally reactive. This kind of food reaction seems to be rather common, except that I've had pain in my kidney area and I haven't heard of anyone else having this symptom. I can have a reaction from a fraction of a milligram of food protein.
My “oral tolerance” mechanism got messed up for whatever reason – celiac disease, bad gut microbes, stress, who knows!
But I have asked myself recently, did I help create this awful situation where I have terrible inhalant allergies AND severe "delayed food allergies" to almost all common foods – by completely avoiding so many foods? Maybe my "oral tolerance" mechanism can heal itself if I eat food allergens in tiny quantities, taking allergy medications beforehand.
I can get oral cromolyn relatively cheaply from a compounding pharmacy. The brand-name version, Gastrocrom, is extremely expensive.
Alternative-medicine practitioners have tried to deal with "delayed food allergies". They generally recommend avoidance of the food, probiotics, and sometimes, special diets. How seriously their recommendations should be taken, is very unclear. There's some evidence in favor of probiotics.