Allergens are substances which can lead to reactions of hypersensitivity (allergic reactions) in humans. In the field of allergology, a distinction is made between test allergens and therapy allergens. In Germany, the Paul-Ehrlich-Institut (PEI) is the competent authority for allergens.
Test allergens serve to detect allergies to the allergen tested. The different testing methods are called epicutaneous, intracutaneous, prick test, and provocation test.
Therapy allergens are used in allergic persons to perform so-called specific immunotherapies (allergen immunotherapy (AIT), hyposensitisation) over a longer period of time to alleviate overreactions of the immune system, or, ideally, to stop them. With regard to therapy allergens, a distinction is made between subcutaneous immune therapy and allergens for sublingual treatment.