What causes acne in women?

Excess testosterone: All women have male hormone, testosterone, in their bodies. An excess can cause acne. This is oftentreated with estrogen, commonly in oral contraceptives. In the bloodstream are compounds called sex hormone binding globulins. Estrogen increases these elements. When sex hormone binding globulin attaches to testosterone, the testosterone is inactivated, ergo less acne.

Many things: Hormones, genetics, hygiene. See your doctor.