Allergies are characterised by unnecessary and excessive immune response to harmless substances like for example pollen. In literature, various classifications of allergic disorders are being discussed. The following chapter makes use of the hypersensitivity reaction types 1-4 that have been outlined by Coombs and Gell 1963.
Type I is the allergy of immediate type. Type II includes the autoimmune diseases. Type III is autoimmune-complex mediated and type IV describes the "autoantibody-free" type, conversely known as delayed hypersensitivity reactions. If the typical allergic symptoms like urticaria, asthma, anaphylaxis or potentially fever, skin rash etcetera occur, a drug hypersensitivity reaction should always be taken into consideration. Therefore, an anamnesis including the drug intake of the last month is needed. Treatment options include a discontinuation of the causative allergen or drug (if possible) by what the symptoms should eliminate within two weeks and symptomatic respectively supportive therapy by corticosteroids and antihistamines.
Type I: hypersensitivity reactions
Type II: autoantibody-mediated cytotoxic reactions
Type III: immune complex-mediated
Type IV: delayed hypersensitivity reactions