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Λεξικό .. Double-blind, placebo-controlled food challenge (DBPCFC)

Double-blind, placebo-controlled food challenge (DBPCFC)

Double-blind placebo-controlled food challenge (DBPCFC) A test in which neither the physician nor the patient know what the patient is being fed. The suspected food is disguised in another food. DBPCFC is the gold standard for diagnosing food allergy. DBPCFC is the method of choice for scientific protocols.DBPCFC’s have taught us that:

- most case histories are inaccurate

- there is short list of foods in 90% of cases

- most children are allergic 1-2 foods only

The final dose of all 3 -- OFC, SBPCFC and DBPCFC, is open and the same -- a normal portion of the suspected food is ingested openly. All negative blind challenges end with an open challenge (OFC).

Double-blind placebo-controlled food challenge (DBPCFC) theoretically is considered the most reliable method to diagnose food allergy because it eliminates both patient and physician bias. In clinical settings though, open food challenge is the most practical test. DBPCFC is not often performed in non-academic allergy setting. For scientific purposes the only accepted test for the confirmation of food allergy/food intolerance (FA/FI) is a properly performed DBPCFC [1].

There is enough experience with the use of double-blind, placebo-controlled, food challenge (DBPCFC), in order to be recommend  as an office procedure for most patients complaining of adverse reactions to foods. 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 [4].

In spite the fact that double-blind, placebo-controlled food challenge (DBPCFC) is widely considered as the 'gold standard' for the diagnosis of food allergy, however, in adult patients, this procedure is rather rarely performed outside the academic context.

Asero R, et al (2009) reappraisd the pros and cons of DBPCFC and elicited some critical thoughts and discussions about the real indications of this diagnostic procedure in adult patients in everyday practice. They found that there are many data showing that the DBPCFC poses a number of critical problems that are difficult to overcome in normal outpatient clinics and hospitals, and that are generally not addressed in most articles dealing with this issue. Performing DBPCFC poses a number of practical problems and has several pitfalls, which make its routine use in normal clinical settings generally impossible. In their review article showed  that the need for this procedure in adult patients seems in effect very little and they specified new, more limited indications to its use in everyday practice. Further, they suggested a role for the open challenge, which lacks several of the disadvantages of DBPCFC [2].

Vlieg-Boerstra BJ,et al (2008) used DBPCFCs in a consecutive series of children with a history of anaphylaxis to foods, and no indications in dietary history that the food allergy had been resolved. In their study showed that in such children having specific IgE levels below established cut-off levels reported in other studies predicting positive challenge outcomes, re-evaluation of clinical reactivity to food by DBPCFC should be considered, even when there are no indications in history that anaphylaxis has resolved. DBPCFCs can be performed safely in these children, although there is a potential risk for severe reactions [3].

References


1. Wüthrich B. Food allergy, food intolerance or functional disorder? Praxis (Bern 1994). 2009 Apr 1;98(7):375-87.

2. Asero R, Fernandez-Rivas M, Knulst AC, Bruijnzeel-Koomen CA. Double-blind, placebo-controlled food challenge in adults in everyday clinical practice: a reappraisal of their limitations and real indicat

3. Vlieg-Boerstra BJ, Duiverman EJ, van der Heide S, Bijleveld CM, Kukler J, Dubois .

Should children with a history of anaphylaxis to foods undergo challenge testing? Clin Exp Allergy. 2008 Dec;38(12):1935-42. Epub 2008 Sep 3

4. Bock SA, Sampson HA, Atkins FM, Zeiger RS, Lehrer S, Sachs M, Bush RK, Metcalfe DD. Double-blind, placebo-controlled food challenge (DBPCFC) as an office procedure: a manual. J Allergy Clin Immunol. 1988 Dec;82(6):986-97.Comment in:J Allergy Clin Immunol. 1990 Jan;85(1 Pt 1):139. J Allergy Clin Immunol. 1991 Jan;87(1 Pt 1):136-7.

Γκέλης Ν.Δ. - Λεξικό Αλλεργίας - Εκδόσεις ΒΕΛΛΕΡOΦΟΝΤΗΣ - Κόρινθος 2013

Gelis Ν.D. - Dictionary of Allergies - VELLEROFONTIS Publications - Corinth 2013