You are breaking out because the ratio between oestrogen and androgens shifts, and the follicles along the jaw respond to androgens. What makes it different from teenage acne is the skin underneath: drier, thinner, slower to repair. Drying it out treats one half and worsens the other.
Sebaceous glands carry androgen receptors, and the jawline, chin and neck are where adult female acne concentrates. As oestrogen falls through the transition while androgen production declines more gradually, the ratio those glands sit in changes. A New Zealand clinical reference attributes acne in menopause to a shift in the relationship between oestrogens and testosterone, and lists antiandrogens, including certain oral contraceptives and spironolactone, among the treatments widely used for persistent acne in women.
Adult acne is a recognised entity with its own shape rather than a leftover from adolescence. It can persist from teenage years or begin after 25, it tends to be mild to moderate, inflammatory lesions are common on the jawline and neck, premenstrual flares are common, and large closed comedones on the chin, cheeks and forehead are more common than in younger people. Acne affects up to 15% of women. A clinical practice guide for adult female acne is explicit that it differs from teenage acne, that genetic and hormonal factors both contribute, and that maintenance treatment is usually needed for years rather than weeks.
The complication specific to this decade is the barrier underneath. The same hormonal shift that changes the oil is thinning the ceramides, sebum and water-holding that seal the surface, so the routine that worked at nineteen now strips a barrier that has nothing spare. That is how women end up with skin that is dry, tight, red and still breaking out, and it is why the first half of this page is about what to stop.
The usual causesa shifted androgen to oestrogen ratioa thinner barrier underneathdrying products meant for teenage skinocclusive make-up and face oilspremenstrual flaressometimes a medicine or supplement