wo macht man allergietest — what are common causes?

The question about allergy testing and common causes is clinically important, but the provided knowledge context does not contain specific information on allergies, allergy tests, or their triggers. The available texts focus on mineral metabolism, iron homeostasis, caffeine metabolism (CYP1A2), and general limitations of direct-to-consumer DNA tests. Therefore, I can only reference general medical knowledge: allergy tests are typically performed by dermatologists, pulmonologists, or specialized allergists using skin prick tests, blood tests (specific IgE), or provocation tests. Common allergy triggers include pollen, dust mites, animal dander, mold, insect venom, and foods (e.g., peanuts, milk, eggs). The evidence for home allergy tests (e.g., IgG-based) is weak and often misleading, as hinted in the Q&A batches. Without direct sources from the context, I must rate the evidence as unclear. For reliable guidance, professional medical diagnosis and current guidelines (e.g., from EAACI) are essential.