Final answer:
Acne is the skin disorder characterized by chronic inflammation of the sebaceous glands, occurring when pores get clogged with sebum and keratin, leading to infection and inflammation.
Step-by-step explanation:
The skin disorder characterized by chronic inflammation of the sebaceous glands from retained secretions is acne. This condition typically affects areas of the skin that are rich in sebaceous glands, such as the face and back. The inflammation of acne occurs when pores become clogged with excess sebum and keratin, leading to whiteheads which turn black upon oxidation. When these clogged pores become infected by acne-causing bacteria, such as Propionibacterium and Staphylococcus, it leads to inflammation, redness, and potentially scarring.