What is a common feature of comedonal acne?

Comedonal acne is characterized primarily by the formation of whiteheads and blackheads, which are both forms of non-inflammatory acne lesions. Whiteheads, or closed comedones, occur when hair follicles become clogged with oil, dead skin cells, and bacteria, leading to the formation of small, flesh-colored bumps under the skin. Blackheads, or open comedones, are similar but occur when the clogged material is exposed to air, causing it to oxidize and turn dark.

In contrast, features such as deep cysts, highly inflamed and painful lesions, and the complete absence of lesions do not typically define comedonal acne. Deep cysts are more often associated with cystic acne, which involves severe inflammation. Highly inflamed lesions indicate a more acute inflammatory process, which is not the case with comedonal acne. The absence of any lesions would suggest a lack of acne altogether, making it incompatible with the definition of comedonal acne. Therefore, the formation of whiteheads and blackheads is the key feature that identifies this type of acne.