Each type of acne technically falls into one of two buckets: non-inflammatory or inflammatory. To be clear, all acne stems from some level of inflammation. (This distinction is a bit of a misnomer, but it helps us distinguish the aesthetic differences.) A few types are more tender, puffy, and angry than others–those are classified as “inflammatory.” Papules, pustules, nodules, and cysts fall into this category, as they’re all typically red and painful.
“Non-inflammatory” acne, on the other hand, results in subtler mounds–these are your whiteheads, blackheads, and subclinical breakouts. Also known as comedonal acne, the bumps tend to be flesh-toned (aside from blackheads, which are darker in color). It’s typically caused by clogged hair follicles and found where the skin is more oily, like the chest, back, and T-zone area of the face.
Non-inflammatory acne can become inflamed later on when there is an overgrowth of bacteria (specifically Cutibacterium acnes), which can cause the release of inflammatory cytokines and messengers to create clinical inflammation. So again, all acne is inflammation on some level.