How can I find the cause of allergies?

Question

Does anyone know how to go about isolating an allergen? For instance, you could remember what you eat all day, but then how do you know which food is the actual allergen?

Do allergens create the allergic reaction right after exposure to them, or does it take a while?

Many thanks

Answer 1

If you really want to know which food or foods are bothering you, keep a notebook.  

Write down each day what you ate, along with the time.  If it's a packaged food, and you empty the package, cut out the ingredient list and clip it in the notebook.

You also might consider that you may be reacting to buildings (toxic building syndrome; molds) or chemicals as well as foods (how about chemicals ON foods?).  Allergic reactions to these things (this applies to food, too, of course) don't have to be sneezing or rashes.  They can be nausea or headaches or even depression.

If you have a reaction, write down what it was, and what time.

For a really good resource on record-keeping, see the book "Is This Your Child?" (for adults, too!) by Dr. Doris Rapp, chapter 9. http://www.amazon.com/This-Your-Child-Do...

IgE-mediated, or classical allergies, usually cause a reaction within a short time after you're exposed.  These reactions are usually respiratory (wheezing, sneezing, runny nose), or involve swelling, hives, or itching resulting in an eczema rash.

But there are other types of reactions, involving IgG or another immunoglobulin, that can take place up to two days after exposure.  I have observed a soy reaction in my son that was delayed between 21-22 hours!  But it was always the same amount of time, so I knew.  After a little while keeping your food and symptom diary, you should be able to make connections, too.  It's not as complex as it sounds--just requires some discipline.

Another option, that would actually require MORE discipline, would be to go on an elimination diet.  This would mean you'd either eat only low-allergy foods for several weeks, before introducing foods back into your diet one by one.  OR you'd eliminate only suspect foods (much easier) for several weeks, before again re-introducing those foods one by one, every 3-4 days.  But if you are not at all sure what's causing the problem, this second type of elimination diet may not work for you.  You can read more about elimination diets at http://www.beyond-food-allergies.com/eli...

If you're really at a loss, especially if you don't have classical-type food allergies, get a blood test.  The ELISA is a test for delayed-reaction food allergies.  Like all allergy tests, it's not completely accurate, but it can really give you some direction! Even if you don't have insurance, this test runs about $150 (depending on where you live, I suppose), and tests dozens of foods. http://www.beyond-food-allergies.com/blo...

Good luck! :)