Diagnostic pitfalls in food allergy in children

Currently, the diagnostic work-up of suspected food allergy includes skin prick tests, the measurement of food specific immunoglobulin E (IgE), and the atopy patch test, and double-blind, placebo-controlled food challenges. However, all of these methods, even double-blind, placebo-controlled food challenges (DBPCFC), may sometimes be misleading. This overview describes several pitfalls for standard diagnostic methods such as problems with irritative skin reactions mimicking IgE-mediated symptoms, the problem of non-IgE-mediated reactions, pitfalls arising from the way foods are prepared or processed, effects of the route of exposure, the role of augmentation factors lowering the threshold value for clinical reactions, the noncomparability of specific IgE decision points, the influence of the timing of diagnostic measures. In addition, the problem of alternative diagnostic measures is discussed. In conclusion, there are several pitfalls in the diagnostic work-up of food allergy, which may be misleading for the physician. Properly performed controlled oral food challenges still represent the gold standard for implementing specific diets in food allergic individuals in order to avoid both unjustified diets, which may lead to severe impairments in growth and development, and to avoid unnecessary symptoms if an underlying food allergy is not correctly identified as a cause for the symptoms of the patient.