Immediate hypersensitivity, also known as Type I hypersensitivity or anaphylaxis, is a rapid allergic reaction that occurs within minutes to hours after exposure to an allergen. In the context of Toxicology, this reaction can be triggered by exposure to certain chemicals, drugs, or venom. It involves the activation of IgE antibodies and the release of mediators like histamine from mast cells and basophils, leading to symptoms such as hives, swelling, and difficulty breathing.
