What is the most common cause of hirsutism in this age group?
Age of onset of hirsutism and rate of progression is important in determining the differential diagnosis. In premenopausal women, PCOS is the most common cause of hirsutism accounting for as many as 70% of cases. The age of onset is typically peripubertal, although it can be masked by use of oral contraceptives. The diagnosis of PCOS is based on meeting 2/3 Rotterdam Criteria in adults and all criteria in adolescents. Non-classical CAH and idiopathic hirsutism have similar age of onset i.e. peripubertal