FYI:Allergies: Dubious Diagnosis and Treatment Stephen Barrett, M.D.Many dubious practitioners claim that food allergies may be responsible for virtually anysymptom a person can have. In support of this claim -- which is false -- they administer varioustests purported to identify offending foods. Claims of this type may seem credible because about25% of people think they are allergic to foods. However, scientific studies have found that onlyabout 6% of children and 1-2% of adults actually have a food allergy, and most people withfood allergies are allergic to less than four foods [1].Cytotoxic TestingThe most notorious such test was cytotoxic testing, which was promoted during the early 1980sby storefront clinics, laboratories, nutrition consultants, chiropractors, and medical doctors.Advocates claimed it could determine sensitivity to food, which they blamed for asthma,arthritis, constipation, diarrhea, hypertension, obesity, stomach disorders, and many otherconditions. However, controlled studies never demonstrated reliability, and some studies foundit highly unreliable [2-5]. For example, one study found that white cells from allergic patientsreacted no differently when exposed to substances known to produce symptoms than whenexposed to substances to which the patients were not sensitive [6]. Government regulatoryactions [7-10] and unfavorable publicity have almost driven cytotoxic testing from the healthmarketplace. But a few practitioners still perform it, and many use similar "food sensitivity"tests.ELISA/ACT TestingAnother test claimed to locate "hidden allergies" is the ELISA/ACT, developed by Russell Jaffe,M.D., Ph.D., and performed by Serammune Physicians Lab (SPL), of Reston, Virginia, whichJaffe directs. According to an SPL brochure: When we think of allergies, we immediately think of an allergy whose symptoms occur within minutes of ingesting a food or chemical. The symptoms include hives and itching. . . . "Hidden" or "delayed" allergies are more difficult to identify because the onset of symptoms is delayed from 2 hours to 5 days and the symptoms range from physical pain to unexplained fatigue. Scientific estimates are that as much as 60% of all illness is due to hidden allergies [11].The brochure states that any of the following may indicate the presence of hidden
allergies:chronic headaches, migraines, difficulty sleeping, dizziness, runny or stuffy nose, postnasal drip,ringing in the ears, earaches, blurred vision, irregular or rapid heartbeat, asthma, nausea andvomiting, constipation, diarrhea, irritable bowel syndrome, hives, skin rashes (psoriasis,eczema), muscle aches, joint pain, arthritis, nervous tension, fatigue, depression, mentaldullness, and difficulty in getting your work done.The ELISA/ACT is performed by culturing the patient's lymphocytes and seeing how they reactto up to 300 foods, minerals, preservatives, and other environmental substances. After the test iscompleted, the practitioner (typically a chiropractor) recommends dietary modification andsupplements. SPL maintains a referral list of practitioners who perform the test and supplierswho can provide "special combinations of the suggested supplements to reduce the number of'pills' you may have to take." In 1994, the complete (300-item) profile plus interpretation cost$695.Although the ELISA/ACT test can assess the levels of certain immune responses, these are notnecessarily related to allergy and have nothing whatsoever to do with a person's need forsupplements. Moreover, many of the symptoms listed in SPL's brochure are unrelated to allergyand are not appropriately treated with supplement products. [Note: This test should not beconfused with the ELISA test, which is a standard test for certain infectious diseases.]Other Dubious TestsIn addition to cytotoxic testing and ELISA/ACT, the following procedures are not valid formanaging food allergies: ALCAT testing, which is said to measure how blood cells react to foods "under conditions designed to mimic what happens when the foods are consumed in real life." [12] NuTron testing, which supposedly measures the "reactivity" of white blood cells to food and other substances, is used design a diet that eliminates foods that cause white cell "activation." Proponents claim that the diet can improve overweight and many other conditions "caused by the release of inflammatory chemicals from the activated white cells." The LEAP Program, in which the Mediator Release Test (MRT) is used to identify "delayed food allergies" and treatment involves dietary manipulation and possibly supplements and/or herbs. Provocative testing, in which substances are injected under the skin in increasing doses until symptoms are reported Sublingual testing, in which suspected foods are placed under the tongue Neutralization, in which progressively smaller doses of substances are administered until the patient no longer reacts Other food immune complex and IgG tests, which assess immune reactions that are common but not necessarily related to allergy Desensitization, in which progressively larger doses of a food are injected. While desensitization may work for hay fever and other allergies related to inhaled substances, it is worthless for foods and can be dangerous. Applied kinesiology, in which the patient's arm strength is tested after test substances are placed in the patient's mouth or hand. Nambudripad's Allergy Elimination Technique (NAET), based on the notion that allergies are caused by "energy blockage" that can be diagnosed with muscle-testing and permanently cured with acupressure and/or acupuncture treatments. Electrodermal skin testing, in which a computerized galvanometer is used to detect supposed "energy imbalances." In 1999, the British Advertising Standards Authority reviewed a pamphlet which alleged that a Bio Resonance Therapy device could help people suffering from headaches, overweight, tiredness, bloating, irritable bowel syndrome, skin rashes, arthritis, and premenstrual tension. In May 1999, after reviewing a manual and other information about the device, the Authority concluded that the claims were unsubstantiated [13]. Proper TestingThe correct way to assess a suspected food allergy or intolerance is to begin with a carefulrecord of food intake and symptoms over a period of several weeks. Symptoms such as swollenlips or eyes, hives, or skin rash may be allergy-related, particularly if they occur within a fewminutes (up to two hours) after eating. Diarrhea may be related to a food intolerance. Vaguesymptoms such as dizziness, weakness, or fatigue are not food-related. The history-takingprocedure should note the suspected foods, the amounts consumed, the length of time betweeningestion and symptoms, whether there is a consistent pattern of symptoms after the food isconsumed, and several other factors. Although nearly any food can cause an allergic reaction, afew foods account for about 90% of reactions. Among adults these foods are peanuts, nuts, fish,and shellfish. Among children, they are egg, milk, peanuts, soy, and wheat [14].If significant symptoms occur, the next step should be to see whether avoiding suspected foodsfor several weeks prevents possible allergy-related symptoms from recurring. If so, thesuspected foods could be reintroduced one at a time to see whether symptoms can bereproduced. However, if the symptoms include hives, vomiting, swollen throat, wheezing, orother difficulty in breathing, continued self-testing could be dangerous, so an allergist should beconsulted.Proper medical evaluation -- done best by an allergist -- will include careful review of yourhistory and skin testing with food extracts (using a prick or puncture technique) to see whether anallergic mechanism is involved in your symptoms. In cases where skin testing might bedangerous, a radioactive allergy sensitivity test (RAST) may be appropriate. The RAST is alaboratory test in which the technician mixes a sample of the patient's blood with various foodextracts to see whether antibodies to food proteins are present in the blood. It is not as reliableas skin testing and is more expensive. A negative prick or RAST test indicates a low probabilityof allergy to the test substance. Positive tests, however, have much less predictive value [1].The only sure way to diagnose an allergy to a suspected food, food coloring, or other additive ischallenge testing in which the patient ingests either the suspected food or a placebo [13]. Thismay be appropriate if the patient's history suggests a food allergy but the skin or RAST tests arenegative. Because dangerous reactions can occur, challenge testing should be done in a hospitalor office that is specially equipped for that purpose.References1. Sicherer SH. Manifestations of food allergy: Evaluation and management. American FamilyPhysician 59:415-424, 1999. 2. American Academy of Allergy: Position statements -- Controversial techniques. Journal ofAllergy and Clinical Immunology 67:333-338, 1980. Reaffirmed in 1984. 3 Chambers VV and others. A study of the reactions of human polymorphonuclear leukocytes tovarious antigens. Journal of Allergy 29:93-102, 1958. 4. Lieberman P and others. Controlled study of the cytotoxic food test. JAMA 231:728, 1974. 5. Benson TE, Arkins JA. Cytotoxic testing for food allergy: Evaluations of reproducibility andcorrelation. Journal of Allergy and Clinical Immunology 58:471-476, 1976. 6. Lehman CW. The leukocytic food allergy test: A study of its reliability and reproducibility.Effect of diet and sublingual food drops on this test. A double-blind study of sublingualprovocative food testing: A study of its efficacy. Annals of Allergy 45:150-158, 1980. 7. Hecht A: Lab warns cow: Don't drink your milk. FDA Consumer 19(6):31-32, 1985. 8. Bartola J: Cytotoxic test for allergies banned in state. Pennsylvania Medicine 88:30, October1985. 9 Proposed notice: Medicare program; Exclusion from Medicare coverage of certain foodallergy tests and treatments. Federal Register 48(162):37716-37718, 1983. 10. Cytotoxic testing for allergic diseases. FDA Compliance Policy Guide 7124.27, 3/19/85. 11. Do you have hidden allergies? ELISA/ACT can help you. Undated brochure distributed in1993 by Serammune Physicians Lab. 12. The ALCAT test: A simple blood test for food and chemical sensitivities (Flyer).Hollywood, FL: AMTL Corporation, 1995. 13. British Advertising Standards Organization. Adjudication: Allergy Testing Service, May1999. 14. Sampson HA. Food allergy. JAMA 278:1888-1894, 1997. For Additional Information University of Iowa Virtual Hospital Quackwatch Home Page | || Other Dubious Tests This article was revised on June 7, 2000. ------------------
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