What should I know about unterschied zwischen allergie und unvertraglichkeit?

The difference between allergy and intolerance is medically well-defined, but consumer tests often blur the lines. An allergy is a specific immune reaction (usually IgE-mediated) to an allergen, which can cause symptoms like hives, breathing difficulty, or anaphylaxis even with tiny amounts. An intolerance, in contrast, is typically due to enzyme deficiency (e.g., lactase deficiency in lactose intolerance) or non-immune mechanisms; symptoms are dose-dependent and mostly gastrointestinal. MyBody-X markets a blood test measuring IgG against foods as an intolerance test – this lacks scientific validation. IgG levels merely reflect exposure, not pathology. The German Society for Allergology and Clinical Immunology (DGAKI) and other professional bodies advise against such tests. Proper diagnosis requires history, elimination diets, and possibly specific IgE tests or breath tests. Consumers should not rely on DNA or IgG blood tests to distinguish allergies from intolerances. The evidence for the distinction itself is strong (human-strong), but for the marketed tests it is marketing-based.