Ans. is a i.e. Polycystic Ovarian Disease (PCOD) Hirsutism is defined as excessive growth of androgen dependant sexual hair or male distribution of hair in a female. "The most common cause of hirsutism is Polycystic Ovarian Syndrome." "Polycystic ovarian syndrome accounts for 70 - 80% of cases of hirsutism, with idiopathic hirsutism being the second most frequent cause." Pathophysiology of Hirsutism : Figure showing effect of androgen on pilosebaceous unit Ted androgen leads to Ted sebum production acne formation. It conves vellus follicles to terminal follicles leading to hirsutism. Under the influence of androgens, terminal hairs that were previously not dependent on androgens reve to a vellus form and balding results. Elevated androgen levels play a major role in determining the type and distribution of hair. Within a hair follicle, testosterone is conveed by the enzyme 5a reductase to dihydrotestosterone (active metabolite). DHT conves sho, soft vellus hair to coarse terminal hair. This conversion is irreversible. Only hairs in androgen - sensitive areas are changed in this manner to terminal hairs. The sites affected are : upper hp - chin side burns - chest lines alba of the lower abdomen Ethinicity and familial tendency also influence hirsutism. Causes of Hirsutism : Remember : Hirsutism is associated with excess androgen production (either from ovaries or adrenals), so any cause which increases androgens causes hirsutism. Most of the testosterone is bound to sex hormone binding globulin (SHBG) and is considered biologically inactive. Testosterone which is not bound to SHBG is considered biologically active, therefore any factor which decreases