Final answer:
Type IV (Delayed-type) hypersensitivity is the reaction that is delayed, taking one to two days to develop, and involves a cell-mediated immune response that can cause symptoms like contact dermatitis.
Step-by-step explanation:
The type of hypersensitivity reaction that is delayed, taking several days to develop, is Type IV (Delayed-type) hypersensitivity. This reaction is a cell-mediated immune response that typically takes about 24 to 72 hours to develop after secondary exposure to an antigen. In this reaction, the sensitization to an antigen causes T-helper cells of the Th1 class to secrete cytokines that recruit macrophages and other phagocytes to the site, as well as activate cytotoxic T cells. Delayed hypersensitivity reactions can cause symptoms such as local tissue lesions or contact dermatitis, and are involved in immune responses to substances like poison ivy and the tuberculin skin test used for tuberculosis screening.