Final answer:
Drug-induced acute urticaria occurs immediately after drug administration in type I hypersensitivity reactions. Symptoms include hives, itching, swelling, and difficulty breathing.
Step-by-step explanation:
Drug-induced acute urticaria occurs immediately after drug administration in type I hypersensitivity reactions.
Type I hypersensitivity is an immediate allergic reaction that involves the release of chemical mediators (such as histamine) from mast cells.
Upon first exposure to an allergen, the body produces IgE antibodies.
These antibodies then bind to mast cells. When the same allergen is encountered again, it binds to the IgE on mast cells, triggering the release of chemical mediators and resulting in an allergic reaction.
For example, when a person takes a medication to which they are allergic, an immediate allergic reaction may occur within minutes.
Symptoms of urticaria or hives can appear on the skin, along with other symptoms like itching, swelling, or difficulty breathing.