What is a characteristic feature of closed comedones?

Closed comedones are commonly known as whiteheads, which is a characteristic feature that distinguishes them from other types of acne lesions. These are small, flesh-colored bumps that occur when a hair follicle becomes clogged with sebum, dead skin cells, and occasionally bacteria but does not come into contact with air. This lack of air prevents oxidation, which is why they remain closed and appear white.

In contrast, other types of lesions, such as blackheads, are open comedones where the blockage is exposed to air, leading to oxidation and a darker appearance. The clue in this question lies in recognizing the specific nature of closed comedones and understanding that they represent a type of non-inflamed acne. Knowing that they are not inflamed areas of skin nor directly associated with bacteria and dead cells in the same way inflamed comedones or active acne lesions are is key to identifying their characteristic feature.