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Keywords:

  • alternative tests;
  • double blind placebo controlled food challenge;
  • food allergy;
  • food intolerance

Complementary/alternative medicines are largely used in clinical practice (1) and so are diagnostic techniques, despite convincing proofs of their validity lack (2). Alternative tests (e.g. kinesiology, leukocytotoxic test, electrodermal tests, iridology and hair analysis) are preferentially utilized in the field of adverse reactions to foods (3), probably because many disorders are classified as ‘food allergies’, despite there is no demonstration of the underlying mechanism. We evaluated the pattern of use and outcomes of complementary alternative tests in patients with a suspect of food allergy/intolerance in real-life. Patients referred with a suspicion of food-related problems, before beginning the standard diagnostic workup, were asked about the previous use of alternative tests. The results obtained with those tests were compared, when possible, to the double blind placebo controlled food challenge (DBPCFC).

One hundred and thirty-two patients were referred for a suspected diagnosis of ‘food allergy’ or ‘food intolerance’ in the period March–December 2003. Out of them, 87 (66%) patients had previously undergone alternative diagnostic tests. Their mean age was 38 year (range 4–72) and 62 were females. The distribution of alternative tests among the 87 patients was: 61% electrodermal testing, 19% kinesiology, 11% cytotoxic test, 5% hair analysis and 4% iridology. The symptoms were: dermatological or gastrointestinal in 54% of patients, respiratory in 36% and behavioural in 8%. Out of 87 patients, alternative tests had provided at least one positive result in 86, being milk, flour, yeast and tomato always positive in all patients. Skin prick tests carried out with a panel of commercial extracts (Stallergenes, Milan, Italy) including: milk, egg, shrimp, codfish, salmon, peanut, soybean, hazelnut, wheat, rice, tomato, carrot and apple) provided negative results in 79/87 patients. Three patients had positive prick test to peanut, three to peanut and soybean, one to wheat and one to shrimps. These positivities, all clinically relevant, were invariantly different from those found by alternative tests. A DBPCFC (4) could be performed in 42 patients, since 36 subjects refused it. The DBPCFC was carried out by commercial liophilized extracts (Test dose, Lofarma SpA, Milan). The cumulative doses given were 85 mg milk, 10 mg yeast, 32 mg wheat and 20 mg egg. The results of the food challenges, compared to those obtained with alternative procedures, are summarized in Table 1. In no case, but one, the positivity of alternative tests was confirmed by the DBPCFC. A subjective response to placebo (itching, malaise, nausea and headache) was invariantly observed in about 50% of subjects.

Table 1.  Results of the DBPFC and of the alternative tests for the same foods
FoodNResults of the DBPCFCPositive results of the alternative tests
PositivePlacebo positiveVEGA TestDRIA testCytotoxic testIridology
Milk26 1/2618/2610/263/2613/26
Yeast70/74/73/71/73/7
Wheat80/84/83/82/83/8
Egg10/10/11/1

Complementary/alternative diagnostic procedures represent a relevant problem for both general practitioner and specialists. In our relatively small population, two-thirds of the subjects had a previous diagnosis made by alternative tests, but a positive result was confirmed only in one case. In other cases, the alternative tests were unable to identify correctly the responsible foods, or provided an unacceptable number of false positives. As a general consideration, the high rate of false positive results leads to time-consuming and useless consultations, with a not negligible resource wasting. Moreover, based on the results of the tests, inappropriate diets were prescribed to many patients. In everyday clinical practice, patients should be advised of the risks and drawbacks of alternative diagnostic techniques (3), especially in the case of suspected food related symptoms.

References

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  2. References
  • 1
    Schafer T. Epidemiology of complementary alternative medicine for asthma and allergy in Europe and Germany. Ann Allergy Asthma Immunol 2004;93(Suppl 1):S5S10.
  • 2
    Niggemann B, Grüber C. Unproven diagnostic procedures in IgE-mediated allergic diseases. Allergy 2004;59: 806808.
  • 3
    Teuber SS, Porch-Curren C. Unproved diagnostic and therapeutic approaches to food allergy and intolerance. Curr Opin Allergy Clin Immunol 2003;3: 217221.
  • 4
    Helm RM. Food allergy: in-vivo diagnostics including challenge. Curr Opin Allergy Clin Immunol 2001;1: 255259.