Medline ® Abstracts for References 1,26-28
of 'Oral food challenges for diagnosis and management of food allergies'
Double-blind, placebo-controlled food challenge (DBPCFC) as an office procedure: a manual.
Bock SA, Sampson HA, Atkins FM, Zeiger RS, Lehrer S, Sachs M, Bush RK, Metcalfe DD
J Allergy Clin Immunol. 1988;82(6):986.
There is now enough experience with the use of double-blind, placebo-controlled, food challenge (DBPCFC) to recommend its use as an office procedure for most patients complaining of adverse reactions to foods. This manual discusses the practical methods required for the allergist to undertake DBPCFC in the office. Thorough histories supplemented by food allergen skin testing are used to design a DBPCFC that carefully attempts to reproduce the history of food-induced symptoms described by the patient. Precautions that must be taken are delineated before challenge, as is treatment that may be required if a reaction occurs. For those foods to which challenges are positive, longitudinal evaluation with repeated challenge at appropriate intervals help to determine whether or not the problem will resolve over a period of time.
National Jewish Center for Immunology and Respiratory Medicine, Denver, Colo. 80206.
Does severity of low-dose, double-blind, placebo-controlled food challenges reflect severity of allergic reactions to peanut in the community?
Hourihane JO, Grimshaw KE, Lewis SA, Briggs RA, Trewin JB, King RM, Kilburn SA, Warner JO
Clin Exp Allergy. 2005;35(9):1227.
BACKGROUND: The severity of allergic reactions to food appears to be affected by many interacting factors. It is uncertain whether challenge-based reactions reflect the severity of past reactions or can predict future risk.
OBJECTIVE: To explore the relationship of a subject's clinical history of past reactions to the severity of reaction elicited by a low-dose, double-blind, placebo-controlled food challenge (DBPCFC) with peanut.
METHOD: Cross-sectional questionnaire assessment of community-based allergic reactions and low-dose DBPCFC in self-selected peanut-allergic subjects. Reaction severity was assessed using a novel scoring system, taking account of the dose of allergen ingested.
RESULTS: Forty subjects (15 males, 23 children, 23 asthmatics by history) were studied. Only the most recent community reaction predicted the severity of reaction in the DBPCFC, but even this association was weak (r=0.37, P=0.03). Peanut-specific IgE (PsIgE) and skin prick test (SPT) weal size were not associated with community score but PsIgE level correlated well with the challenge score (r=0.6, P=0.001). Asthma did not affect the eliciting dose or challenge score directly but the association of PsIgE and challenge score was stronger in those without asthma (r=0.72, P=0.001) than in those with asthma (r=0.48, P=0.02).
CONCLUSIONS: The scoring system developed appears to improve the sensitivity of assessment of reactions induced by DBPCFC. This is the first prospective study showing an association between PsIgE levels and clinical reactivity in DBPCFC, an effect that is more pronounced in non-asthmatics. This finding has important implications for the clinical care of subjects with food allergy. There is a poor correlation between the severity of reported reactions in the community and the severity of reaction elicited during low-dose DBPCFC with peanut.
Allergy&Inflammation Research (Child Health), University of Southampton, Southampton, UK. J.Hourihane@ucc.ie
Anaphylactic shock during elimination diets for severe atopic eczema.
Arch Dis Child. 1984;59(10):983.
Eighty patients with atopic eczema were treated with various elimination diets. Some or all foods were withdrawn then later reintroduced singly to the diet. In four patients reintroduction of a single food (soya, chicken, corn, cows' milk) caused anaphylactic shock. In two patients spontaneous recovery occurred but in two resuscitation and intensive care were required. Anaphylaxis is a definite hazard of these elimination diets. Other than warning the parents, practical precautions are difficult because of the unpredictability of violent reactions and uncertainty about the life saving efficacy of injected adrenaline.
Acute allergic reactions in children with AEDS after prolonged cow's milk elimination diets.
Flinterman AE, Knulst AC, Meijer Y, Bruijnzeel-Koomen CA, Pasmans SG
BACKGROUND: Food allergy is not always correctly diagnosed in children with atopic eczema dermatitis syndrome (AEDS) and treatment with an avoidance diet is not without danger.
METHODS: After admission to our clinic, 11 children with a prolonged cow's milk (CM) elimination diet because of AEDS and sensitization underwent double-blind placebo-controlled food challenge (DBPCFC). Retrospectively, the exposure to CM, sensitization and reactions to accidental ingestion were carefully documented. The DBPCFC was used to evaluate the childrens' current status.
RESULTS: Before the elimination period (median 2.3 years; started before the admission) all 11 children with AEDS were sensitized and had ingested CM (four bottle-fed; seven breast-fed without CM diet of the mother) without the development of acute reactions. The diagnosis of CM allergy was not confirmed by DBPCFC previously. After elimination the AEDS had not improved, but nevertheless the diet was continued. During the elimination period, eight of 11 children developed severe acute allergic reactions to CM after accidental ingestion. In evaluation, in our clinic all 11 children experienced acute allergic reactions to CM during DBPCFC.
CONCLUSION: There is a considerable chance of developing acute allergic reactions to CM after elimination in children with AEDS without previous problems after CM intake.
Department of Dermatology/Allergology, University Medical Centre, Utrecht, Utrecht, the Netherlands.