Tăng chức năng tuyến bã nhờn có tầm quan trọng lớn trong nguyên nhân của mụn trứng cá. Nhiên liệu bằng cách kích thích quá của các thụ thể androgen, một dư thừa bã nhờn được sản xuất. Sau này, có sự thay đổi trong mô hình của keratinization nang với cornification của infrainfundibulum của tuyến bã nhờn. | Increased sebaceous gland function is of major importance in the etiology of acne. Fueled by overstimulation of the androgen receptors an excess of sebum is produced. Following this there are changes in the pattern of follicular keratinization with cornification of the infrainfundibulum of the sebaceous gland. This results in impaired drainage and consequently the formation of comedones. Abnormal microbial colonization of the pilosebaceous duct by Proprionibacterium acnes is the next step down the acne pathway which terminates in inflammation. Although acne and hirsutism are both androgen driven conditions both involving the single morphological entity of the pilosebaceous unit and quite often presenting simultaneously especially in PCOS they do not always appear concomitantly. It was hypothesized therefore that there may be some dichotomy in the final pathway of endocrine pathogenesis and indeed it was found that dihydrotestosterone is further reduced to 3a-androstanediol and its glucuroner-ide only in hirsute patients but not in acne patients 13 . It was concluded that dihydrotestosterone may undergo different metabolic pathways at skin level supporting the hypothesis that the two clinical entities may be expressions of the different metabolic fate of dihydrotestosterone itself. The etiology of acne in early adolescence has been associated with increasing serum levels of DHEAS whereas hirsutism has been more directly linked with high concentrations of free testosterone. The two structures comprising the pilosebaceous unit may have different degrees of sensitivity to similar androgenic stimulation 13 . The hormonal profile of women who have acne and ultrasonically demonstrated polycystic ovaries compared with women who have acne but morphologically normal ovaries differs 10 . Those with polycystic ovaries had raised concentrations of androstendione DHEA DHEAS and LH FSH ratio compared to those with normal ovaries. However within the group of women with polycystic
