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ALLERGIES

A food allergy is caused by an immune reaction to a normally
harmless protein in the food. The protein is called an allergen due
to the fact that it can cause an allergic reaction.

Food intolerance may be due to various factors, usual IgE testing discussed above. Patch testing is typically used to
including: diagnose allergic contact dermatitis to a variety of chemicals, metals
• Enzyme deficiency, such as lactose intolerance etc., which are a delayed or Type 4 hypersensitivity reaction. This
• Chemicals that are produced naturally in foods such as salicylates involves applying the food (or chemical) to the back for 48 hours,
and then checking for an allergic response over the next several days.
in plant foods like fruit, vegetables and spices, amines in protein
foods like chocolate, cheese, less-than-fresh meats and seafood, Other Tests:
and histamine in improperly stored fish (Scombroid poisoning) There are other food allergy tests on the market, e.g. measuring
and in foods like strawberries, chocolate and ripe cheese. Also,
there are chemicals in foods that may affect people who suffer IgG levels to foods, or white blood cell reactions to foods, however,
from allergic contact dermatitis. For example, foods high in neither have been scientifically proven and therefore are not covered
nickel, such as chocolate, cashews, kidney beans and spinach, may by insurance. These tests have a high number of false positives, es-
cause dermatitis, especially hand dermatitis, in people who suffer pecially if that food is frequently eaten. Avoiding common foods,
from contact dermatitis to fake jewelry, belt buckles, etc. such as gluten and dairy, may lead to overall improvement in how
• Food additives, artificial sweeteners, colorings or flavorings, one feels and maybe even weight loss, but that does not prove that
preservatives, emulsifiers and antioxidants. Some examples of a person is truly allergic to those foods.
preservatives are benzoates, nitrates, MSG, as well as, sulfites.
• Autoimmune disease, celiac disease is both an autoimmune dis- Preventative Treatment:
ease and a gluten intolerance. Unfortunately, the only recommended preventative therapy for

DIAGNOSIS: food allergy is avoidance. Oral and sublingual food desensitization
Skin Testing/Serum IgE testing: are both being investigated, but there are some practitioners who
are currently offering the service in their clinics. A topical patch for
In diagnosing a food allergy or intolerance, a good history is vital, peanut allergy is also being studied, as well as Xolair injections and
as the story must correlate with the lab test. The most commonly a mixture of herbs named Chinese Herbal Formula.
used food allergy testing mechanisms include skin testing and Im-
munoCap IgE blood testing. It is extremely important to remember In patients with multiple food allergies, especially infants and
that both methods can produce false positive reactions. A patient growing children, the help of a registered dietician and nutritionist,
with a positive food test, who has been consuming that food without to ensure proper nutrition, is encouraged.
any symptoms, should not be advised to avoid that food.
Victor Estrada, MD, MPH is board certified in allergy and im-
Also, remember that false negatives occur if the reaction is not a munology, with over 27 years of experience treating children and adults.
Type 1 hypersensitivity reaction or IgE mediated. Many times, a
food diary documenting all foods eaten, plus all symptoms experi-
enced, are required. This may require the assistance of a registered
dietician. Other times, if a patient is motivated, a very restrictive
elimination diet, such as chicken, rice and water only, for several
days, may be more appropriate. If the symptoms improve, then one
new food every 5 - 7 days, can be re-introduced.

Patch Testing:
In infants and young children diagnosed with eczema or atopic

dermatitis, some centers are adding patch testing of foods to the

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