Acne-prone skin
During adolescence, oily skin can easily become acne-prone with blackheads and spots. The biological cause of this change is an increase in the quantity of sebum (hyperseborrhoea), combined with a change in sebum quality (dysseborrhoea). Acne is also common among 40% of adults worldwide, although it is more common among women than men.
Thickened skin, clogged pores, blocked sebum, bacterial growth... a vicious cycle sets in and comedones turn into inflamed red spots. Other factors such as the environment and personal diet also play a role in acne.