What it is
Inside the hair follicle, keratinocytes normally shed and exit. In acne-prone follicles, they shed too quickly and clump together.
This abnormal keratinization, combined with sebum, contributes to comedone formation — the structural seed of most acne lesions.
Retinoids normalize this turnover, which is why they are central in acne mechanism maps.
Why it matters
It is one of the earliest events in the acne sequence; addressing it addresses many later steps.