What characterizes non-inflammatory acne?

Non-inflammatory acne is primarily characterized by the presence of comedones, which include whiteheads and blackheads. These types of acne lesions occur when hair follicles become clogged with excess oil (sebum), dead skin cells, and sometimes bacteria, but they do not provoke the body's inflammatory response. Whiteheads are closed comedones, while blackheads are open comedones exposed to air, which causes oxidation and leads to the black appearance.

In contrast, the presence of cysts suggests a more severe form of acne that is typically inflammatory, while severe redness often accompanies inflammatory acne conditions. Pustules and papules also indicate an inflammatory response, as they are associated with redness and swelling due to infection and irritation in the hair follicles. Therefore, the defining feature of non-inflammatory acne is indeed the presence of whiteheads and blackheads.