The development of hypersensitivity as a result of repeated exposure to an allergen over time is called:

The development of hypersensitivity due to repeated exposure to an allergen is described as sensitization. This process involves the immune system becoming more reactive to an allergen after initial encounters. When a person is first exposed to an allergen, their immune system may not react strongly, but the body begins to produce specific antibodies, called Immunoglobulin E (IgE), against that allergen.

As repeat exposures occur, the immune system "remembers" the allergen and responds more aggressively upon subsequent contact. This heightened response can lead to symptoms of allergy, which can range from mild to severe, depending on the individual and the quantity of the allergen encountered. Sensitization is a key concept in understanding how allergies develop and why some individuals experience strong allergic reactions after multiple exposures.

Other terms listed, such as allergy, desensitization, and immune response, do not specifically address the initial process of developing hypersensitivity through repeated exposure. Allergy refers to the outcome or result of sensitization, desensitization describes a process aimed at reducing the immune response to allergens, and immune response is a broader term that encompasses various actions taken by the immune system to defend against pathogens or allergens.