welche allergien gibt es — what does this mean exactly?

The question 'which allergies are there' asks about the different types of allergies, classified by trigger and immune mechanism. Medically established categories include: Type I (IgE-mediated, e.g., pollen, dust mites, pet dander, foods like peanuts, insect venom), Type II (cytotoxic, e.g., drug allergies), Type III (immune complex, e.g., serum sickness), and Type IV (T-cell-mediated, e.g., contact allergies to nickel or fragrances). In everyday practice, Type I (immediate) and Type IV (delayed) are most relevant. It is important to distinguish allergies from pseudo-allergies (e.g., histamine intolerance) and food intolerances (lactose, fructose), which are not true allergies. Direct-to-consumer tests (e.g., DNA tests) may indicate certain genetic risk factors but cannot replace medical diagnosis with specific IgE blood tests or skin prick tests. The evidence for this classification is strong, but clinical relevance depends on individual exposure and symptoms.