T Symposium on Pediatric Allergy

Food Allergy A Commentary

Charles D. May, M.D.*

Clinical allergy suffers from two especially troublesome areas of uncertainty-diagnosis of food allergy and use of injection of allergen extracts as a mode of therapy. t Lack of sound knowledge in these fields allows loose opinion and strong feeling to encroach upon rational practice. Physicians occupied in more advanced sections of clinical medicine are apt to view the spectacle with disdain. Actually such troublesome areas of uncertainty are contemporary examples of the ways men have gathered their opinions on care of the sick throughout the tortuous course of medical history. One way to form opinions is by intuition-a dependence on a process of revelation or spontaneity whereby the worth of an opinion is judged by the intensity of feeling of belief engendered. We all have opinions reached in this way, especially where hard facts are not in the path of our fancy, Another basis for an opinion is knowledge derived by the scientific method, a process whereby hypotheses are tested by objective observations and controlled experiments. Adoption of the scientific method as the most reliable means of development of trustworthy medical care has become general only in relatively recent times and is still not universal, as some current practices testify. Two essential features of the scientific method are: (I) the collection of observations upon which competent investigators can agree, and (2) the provision of controls in manipulations devised to answer questions. This means objective procedures must be employed to lessen the influence of personal bias. If these considerations were kept in mind, the more troublesome uncertainties in clinical allergy could be attacked with greater promise. Controversy over inadequate observations and uncontrolled experience leads to unwholesome schism in the profession and loss of confidence by the public. No one faction is likely to possess all the truth; any factions *Professor of Pediatrics, University of Colorado School of Medicine, Denver, Senior Staff, Division of Pediatric Allergy, National Jewish Hospital and Research Center, Denver, Colorado tDiscussed by the author elsewhere in this symposium.

Pediatric Clinics of North America- Vol. 22, No. 1, February 1975

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claiming to pursue the truth with scientific methods must yield to the demands of objective observations and controlled trials. Only those who subscribe to scientific methods can hope to engage in rational discussions.

Food Allergy Our troubles begin when we leap from a suspicion that ingestion of a food has caused symptoms to the assumption this is due to allergy, particularly when liberties are taken with the meaning of the term allergy. "Allergy" was introduced by von Pirquet to denote change in reactivity to substances, particularly when based on antigen-antibody reactions. Through subsequent custom, proper use of "allergy" carries the implication of immune mechanisms, and not just any unusual reactivity. Proper use of words cannot be enforced but depends on cultivated taste. Unusual symptoms one may observe after a food is eaten had better be termed initially an adverse reaction, which could result from a variety of causes, namely, deficiency of an intestinal enzyme, chemical or parasitic contaminants in the food, psychologic factors, as well as immunologic (allergic) and unknown causes. To eliminate the possibility that psychologic factors or observer bias may play a dominant role, one must provide the suspected food in some hidden fashion, as by opaque capsules containing the food on one occasion and a benign or inert material on another, the order being unknown to patient or observers. Verification of the association of adverse reactions with a food in this manner has rarely been described in published reports and is not common practice. This precaution is especially important in evaluation of vague subjective complaints ascribed to foods by patient or physician. When foods suspected of causing adverse reactions are given blindly, the suspicions may not be confirmed. Unless reactions can be confirmed objectively, there is nothing worthy of study or discussion except the wondrous deceptive powers of the imagination. A prime example is the popular tension-fatigue syndrome. From 1916 to date, 12 papers from 10 authors have appeared on the subject in the periodicalliterature. 1- 12 Three papers do not contain even case reports to sustain the opinions expressed. There are 100 case reports in the other 9 papers, 70 of which are contained in two papers. Twenty of the cases are in a paper which is a collection gathered by questionnaire. The most substantial documentation is in a paper 11 reporting 50 cases, but in only one case was the food administered blindly. The observations in the 50 cases were preponderantly subjective: fatigue-78 per cent; hyperkinesis, irritability-52 per cent; abdominal discomfort-32 per cent; headache- 20 per cent; pallor- 70 per cent. Although some astute clinical observations may well be enmeshed in this clutter, the true nature and incidence of subtle reactions to food will never be determined without objective, controlled observations. Couple these considerations with therealization that about 35 per cent of persons with subjective complaints will be relieved by a placebo, 13 and the hesitancy of rational physicians to accept the tension-fatigue as a common reaction to foods without better documentation seems justified in modern clinical medicine.

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A sound approach to clinical diagnosis of allergy to a food on immunologic grounds would entail extensive characterization of the antigens and antibodies involved in the pathogenesis of symptoms through their interactions with the tissues. The complexity of the antigenic constituents in foods and the enormous variety of specific antibodies induced in the characteristic heterogeneous response to each antigen, along with the variable responses of tissues, mean that simple diagnostic clinical tests of immunologically specific hypersensitivity to foods may never be developed. The devotees of the scientific method are in the same predicament at present as those who claim symptoms to be due to a food without proposing a cause open to examination. Both must rely on sound clinical observation of the effects of elimination or ingestion of a suspected food. "Ay, there's the rub," for in our observations what self-deception may take place. In the absence of means for rigorous identification of the immunologic mechanisms, uncritical claims of relations of foods to symptoms can be expected, and unsupported "systems" of diagnosis and treatment will flourish. Those who resort to dubious practices will surely be shunned by adherents of the scientific method in clinical medicine. The afflicted and the uncritical will join in creating another quackery by resorting to some "system" as a crutch to hobble along with until better means of relief can be found. Rather than calling food "allergy" the "Great Masquerader" 14 among causes of a long list of subjective complaints (e.g., tension-fatigue), common to those overwhelmed with the trials and tribulations of life, this use of food "allergy" may be recognized as the Current Crutch. Such has been the story of quackery, and so it will always be until the last gaps in our knowledge are filled. Stamp it out in one area and it will crop up elsewhere-in cancer, arthritis, epilepsy, or neuroses. Only more light can relieve the darkness. Energy and resources should be devoted to sound research, undistracted by flimsy testimonials and preachers of dubious beliefs. The substantial observations may then be culled from the welter of impressions. An orthodox review of the present state of our knowledge of true food allergy will be found elsewhwere. 15

REFERENCES 1. Hoobler, B. R.: Some early symptoms suggesting protein sensitization in infancy. Am. J. Dis. Child., 12:129, 1916. 2. Shannon, W. R.: Neuropathic manifestations in infants and children as a result of anaphylactic reaction to foods contained in their dietary. Am. J. Dis. Child., 24:89, 1922. 3. Kahn, I. S.: Pollen toxemia in children. J.A.M.A., 88:241, 1927. 4. Rowe, A. H.: Allergic toxemia and migraine due to food. Calif. Western Med., 33:785,1930. 5. Sternberg, L.: Seasonal somnolence, a possible pollen allergy. J. Allergy, 14:89, 1942. 6. Randolph, T. G.: Fatigue and weakness of allergic origin (allergic toxemia) to be differentiated from "nervous fatigue" or neurasthenia. Ann. Allerg., 3:418, 1945. 7. Randolph, T. G.: Allergy as a causative factor offatigue, irritability, and behavior problems of children. J. Pediat., 31:560, 194 7. 8. Clarke, T. W.; The relation of allergy to character problems in children. Ann. Allerg., 8:175, 1950.

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9. Speer, F.: The allergic tension-fatigue syndrome. Ped. Clin. N. Am., 1:1029, 1954. 10. Speer, F.: The allergic tension-fatigue syndrome in children. Int. Arch. Allerg., 12:207, 1958. 11. Crook, W. G., et al.: Systemic manifestations due to allergy. Pediatrics, 27:790, 1961. 12. Deamer, W. C.: Pediatric allergy: Some impressions gained over a 37-year period. Pediatrics, 48:930, 1970. 13. Lasagna, et al.: A study of the placebo response. Am. J. Med., 16:770, 1954. 14. Crook, W. G.: Your Allergic Child. New York, Medcom Press, 1973, pp. 54-67. 15. May, C. D.: Food allergy. In Fomon, S. J. (ed.): Infant Nutrition, 2nd ed. Philadelphia, W. B. Saunders Co., 1974, Ch. 17. 3800 E. Colfax Avenue Denver, Colorado 80206

Food allergy: a commentary.

T Symposium on Pediatric Allergy Food Allergy A Commentary Charles D. May, M.D.* Clinical allergy suffers from two especially troublesome areas of...
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