Hypersensitivity Reaction

An exaggerated or inappropriate immune response to a drug or antigen, classified by the Gell and Coombs system into four types: Type I (IgE-mediated, immediate), Type II (antibody-mediated cytotoxicity), Type III (immune complex), and Type IV (delayed-type, T-cell mediated). Drug hypersensitivity is a major cause of adverse drug reactions and can range from mild rash to fatal anaphylaxis.

Exemplos

• Type I: Penicillin anaphylaxis (IgE-mediated)
• Type II: Heparin-induced thrombocytopenia (antibody-mediated)
• Type IV: Stevens-Johnson syndrome from carbamazepine (T-cell mediated)