Final answer:
Hypersensitivity involves an exaggerated immune response to harmless substances and includes conditions like allergies and asthma. It can result in skin disorders such as eczema and acne, the latter caused by clogged and infected sebaceous glands. Sebaceous adenitis is another skin disorder, which is characterized by inflammation of the sebaceous glands.
Step-by-step explanation:
Hypersensitivity refers to an exaggerated response by the immune system to a substance that is ordinarily harmless. This overreaction can manifest in various forms, including allergies such as hay fever, atopic dermatitis, allergic asthma, and anaphylaxis. The substances that trigger such reactions are called allergens and can include items like pollen, animal dander, and certain foods.
One specific type of hypersensitivity is type I hypersensitivity, which involves a rapid, almost immediate immune response upon re-exposure to an allergen after an individual has been sensitized. This response is mediated by IgE antibodies that sensitize mast cells, leading to inflammation and symptoms like itchy rashes and sneezing.
Common skin disorders associated with hypersensitivity include eczema, an inflammatory condition, and acne, which is the result of clogged pores. Acne particularly occurs in areas rich in sebaceous glands like the face and back and can lead to infection and inflammation due to the overproduction of sebum and blockage of hair follicles.
Although not the focus of the question, it's worth noting that Sebaceous adenitis is a rare skin disorder affecting the sebaceous glands, leading to inflammation and possible hair loss. It is not the same as acne, which involves infected sebaceous glands.