An eminent American allergist has charged that a recent well publicized study supposedly proving that food allergies are all in the head is seriously flawed.
Dr Joseph B. Miller, of the Miller Center for Allergy in Mobile, Alabama, has recently written to the New England Journal of Medicine, charging that the study they published in the l6 August issue which was widely quoted in the national press “contained l3 fundamental errors which made it totally irrelevant and useless”.The study referred to by Miller was a double blind trial supposedly testing the “skin prick” method of diagnosing allergy and the “desensitization” method of neutralizing allergy reaction.
With this method, a specialist tests for allergies by pricking the skin with various potential allergens. He then skin pricks the patients with a variety of strengths of the allergic substance until he discovers a concentration that produces a large allergic response.
Once he has discovered that level, he reduces the strength until he discovers the “neutralizing dose” the dose that has been found to “turn off” symptoms of the allergy.
In the New England Journal of Medicine study, l8 patients were given alternating doses of substances they were supposedly allergic to and then dilutions of saline (the placebo). The seven doctors involved in the study, described as “proponents of this technique and experienced in its use”, were to evaluate allergic symptoms such as nasal stuffiness, headache or fatigue resulting from the skin pricks.
According to the study, designed by the Department of Orthopaedic Surgery and Psychiatry at the University of California, in San Francisco, “the responses of the patients to the active and control injections were indistinguishable”; about the same number of patients thought the control substance was the real allergen as did those receiving the real thing.
Furthermore, said the study, “neutralizing doses given by some of the physicians to treat the symptoms after a response were equally efficacious whether the injection was of the suspected allergen or saline.”
These explosive results prompted large stories in the Sunday Times and an editorial in the same issue of the New England Journal entitled “Food Sensitivity or Self Deception?”which made reference to one study of supposedly allergic people predominantly “professional” types, noted the editorial who were subsequently found out to have psychiatric problems like hysterical neurosis.
Ann Ferguson of the University of Edinburgh, who wrote the editorial, called allergy specialists and other clinical ecologists “well meaning”. She went on to say that when she’s confronted with a supposed victim of allergies she automatically books in twice her usual consultation time in order to give him or her time to “elaborate what may be a long, rambling story”. If an elimination diet doesn’t work, she refers them to psychiatric counseling.
Against what appears to be a backlash against the existence of allergies, Dr Miller, who pioneered the desensitization technique, pointed out what he considers a fundamental flaw in Dr Jewett’s study. For one thing, he notes, Jewett based his conclusions on the assumption that skin pricking and desensitization should produce the very symptoms caused by the offending food itself.
According to Miller, both diagnoses of allergy and neutralizing doses are determined by localized skin reactions (wheals on the skin at the site of the skin prick).
“Symptoms occurred in only l3.5 per cent of l3,423 consecutive successful intradermal neutralizing tests for allergenic foods and inhalants recently analyzed in my office, ” he said. Consequently, patients would be hard pressed to identify which was the allergen and which, the placebo.
Furthermore, he explains, a neutralizing dose employs the strongest concentration which doesn’t produce a skin wheal. The study’s definition of a neutralizing dose, says Miller, “is the definition of an overdose!”