— The current tools available for diagnosing food allergy include the clinical history, physical examination, trial elimination diets, diet diaries, prick/puncture skin testing, and in vitro food-specific IgE testing. Clinician-supervised oral food challenges are often required to confirm or rule out presence or resolution of a food allergy because of the limitations in the diagnostic accuracy of these methods.
Improved or new testing methodologies are needed for determining the presence and severity of a food allergy and the likelihood of resolution of an allergy . This topic reviews improvements in available diagnostic tools and new testing methods that are in development. Current diagnostic tools are discussed separately, as is the initial evaluation of a patient with suspected food allergy. (See “Diagnostic tools for food allergy” and see “History and physical examination in the patient with possible food allergy”).
An important concept regarding IgE-mediated food allergy is the distinction between sensitization and allergy. Sensitization refers to the presence of IgE capable of binding to a particular antigen. Production of specific IgE is necessary, but not sufficient, for clinical allergy. Individuals may have positive testing (skin or in vitro) and yet fully tolerate the antigen in the diet.
Beyond accurate diagnosis of food allergy, there are some closely related prognostic questions confronting food allergic patients, their families, and health care providers. Two of the most common questions are: “Who is at risk for anaphylaxis?” and, for children, ” Will the allergy be outgrown?”.
IgE epitopes — Food allergens must survive digestion and absorption from the gastrointestinal tract to induce systemic reactions. This fact has lead to the hypothesis that individuals who have IgE antibodies recognizing a greater number or a specific pattern of sequential epitopes (not easily destroyed by denaturation and partial digestion) are more likely to have clinical allergy rather than asymptomatic IgE sensitization .
DR WIDODO JUDARWANTO SpA
children’s ALLERGY CLINIC
JL TAMAN BENDUNGAN ASAHAN 5 JAKARTA PUSAT, JAKARTA INDONESIA 10210
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