Allergies: Dubious
Diagnosis and Treatment

Stephen Barrett, M.D.

Many dubious practitioners claim that food allergies may be responsible for virtually any symptom a person can have. In support of this claim—which is false—they administer various tests purported to identify offending foods. Claims of this type may seem credible because about 25% of people think they are allergic to foods. However, scientific studies have found that only about 6% of children and 1-2% of adults actually have a food allergy, and most people with food allergies are allergic to less than four foods [1].

Cytotoxic Testing

The most notorious such test was cytotoxic testing, which was promoted during the early 1980s by 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 other conditions. However, controlled studies never demonstrated reliability, and some studies found it highly unreliable [2-5]. For example, one study found that white cells from allergic patients reacted no differently when exposed to substances known to produce symptoms than when exposed to substances to which the patients were not sensitive [6]. Government regulatory actions [7-10] and unfavorable publicity have almost driven cytotoxic testing from the health marketplace. But a few practitioners still perform it, and many use similar "food sensitivity" tests.

ELISA/ACT Testing

Another 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, which Jaffe 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 and vomiting, constipation, diarrhea, irritable bowel syndrome, hives, skin rashes (psoriasis, eczema), muscle aches, joint pain, arthritis, nervous tension, fatigue, depression, mental dullness, and difficulty in getting your work done.

The ELISA/ACT is performed by culturing the patient's lymphocytes and seeing how they react to up to 300 foods, minerals, preservatives, and other environmental substances. After the test is completed, the practitioner (typically a chiropractor) recommends dietary modification and supplements. SPL maintains a referral list of practitioners who perform the test and suppliers who 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 not necessarily related to allergy and have nothing whatsoever to do with a person's need for supplements. Moreover, many of the symptoms listed in SPL's brochure are unrelated to allergy and are not appropriately treated with supplement products. [Note: This test should not be confused with the ELISA test, which is a standard test for certain infectious diseases.]

Other Dubious Tests

In addition to cytotoxic testing and ELISA/ACT, the following procedures are not valid for managing food allergies:

Proper Testing

The correct way to assess a suspected food allergy or intolerance is to begin with a careful record of food intake and symptoms over a period of several weeks. Symptoms such as swollen lips or eyes, hives, or skin rash may be allergy-related, particularly if they occur within a few minutes (up to two hours) after eating. Diarrhea may be related to a food intolerance. Vague symptoms such as dizziness, weakness, or fatigue are unlikely to be food-related. The history-taking procedure should note the suspected foods, the amounts consumed, the length of time between ingestion and symptoms, whether there is a consistent pattern of symptoms after the food is consumed, and several other factors. Although nearly any food can cause an allergic reaction, a few 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 foods for several weeks prevents possible allergy-related symptoms from recurring. If so, the suspected foods could be reintroduced one at a time to see whether symptoms can be reproduced. However, if the symptoms include hives, vomiting, swollen throat, wheezing, or other difficulty in breathing, continued self-testing could be dangerous, so an allergist should be consulted.

Proper medical evaluation—done best by an allergist—will include careful review of your history and skin testing with food extracts (using a prick or puncture technique) to see whether an allergic mechanism is involved in your symptoms. In cases where skin testing might be dangerous, a radioactive allergy sensitivity test (RAST) may be appropriate. The RAST is a laboratory test in which the technician mixes a sample of the patient's blood with various food extracts to see whether antibodies to food proteins are present in the blood. It is not as reliable as skin testing and is more expensive. A negative prick or RAST test indicates a low probability of 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 is challenge testing in which the patient ingests either the suspected food or a placebo [14]. This may be appropriate if the patient's history suggests a food allergy but the skin or RAST tests are negative. Because dangerous reactions can occur, challenge testing should be done in a hospital or office that is specially equipped for that purpose.

For Additional Information

References

  1. Sicherer SH. Manifestations of food allergy: Evaluation and management. American Family Physician 59:415-424, 1999.
  2. American Academy of Allergy: Position statements—Controversial techniques. Journal of Allergy and Clinical Immunology 67:333-338, 1980. Reaffirmed in 1984.
  3. Chambers VV and others. A study of the reactions of human polymorphonuclear leukocytes to various 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 and correlation. 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 sublingual provocative 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, October 1985.
  9. Proposed notice: Medicare program; Exclusion from Medicare coverage of certain food allergy tests and treatments. Federal Register 48(162):37716-37718, 1983.
  10. Cytotoxic testing for allergic diseases. FDA Compliance Policy Guide 7124.27, March 19, 1985, revised March 1995.
  11. Do you have hidden allergies? ELISA/ACT can help you. Undated brochure distributed in 1993 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, May 1999.
  14. Sampson HA. Food allergy. JAMA 278:1888-1894, 1997.

This article was revised on May 31, 2011.