Adult acne refers to acne over the age of 25 years. One type of acne is persistent acne, which refers to the onset of acne before the age of 25 years, with clinical manifestations continuing beyond the age of 25 years; the other type is late-onset acne, which refers to the first onset of acne after the age of 25 years. A third subtype of recurrent acne has also been proposed, which refers to the onset of acne during adolescence, with the rash fading for several years and reoccurring in adulthood, and these patients generally do not have hyperandrogenemia. Several data in the literature show that the incidence of adult acne is higher in women than in men. The reason for this difference may be that female patients are more demanding in terms of appearance and are more likely to seek treatment because they cannot tolerate the facial irritability and scarring associated with acne. The four main pathogenic factors include increased sebum production by the sebaceous glands, hyperkeratosis of the sebaceous ducts, proliferation of Propionibacterium acnes, inflammatory response, and immune response. The pathogenesis associated with female adult acne is hyperandrogenemia, increased cutaneous androgenic activity, the presence of drug-resistant strains of Propionibacterium acnes, and chronic stimulation by intrinsic immunity. Serum insulin-like growth factor-1, serum low-density lipoprotein, stress, smoking, ultraviolet light, inappropriate use of cosmetics and consumption of high-sugar foods are predisposing or aggravating factors. Polycystic ovary syndrome is the first endocrine disorder to be investigated, with emphasis on hormone levels, as well as gynecological disorders such as uterine fibroids, ovarian cysts and chronic pelvic inflammatory disease.