Hirsutism · What Is It, Causes, Treatment, and More

The causes of hirsutism can be divided into androgenic, non-androgenic, and idiopathic (i.e., the underlying cause is unknown). Androgens, including testosterone, dihydrotestosterone, and their prohormones, act on the hair follicles of sex-related areas of the body to convert fair, vellus hair to larger, coarser, and darker terminal hair. 

The majority of cases of hirsutism are caused by polycystic ovary syndrome (PCOS), which is characterized by excess androgen levels, menstrual irregularities, and ovarian cysts on an ultrasound. Other causes of increased androgen levels include non-classic congenital adrenal hyperplasia; androgen secreting tumors of the ovary or the adrenal gland; and ovarian hyperthecosis, which is when the ovarian follicles secrete increased amounts of testosterone due to hyperplasia of the theca layer. 

On the other hand, non-androgenic causes of hirsutism include medication-related side effects, which can be caused by corticosteroids; exogenous androgens, like danazol; and certain immune modulating agents, like cyclosporine. It can also be caused by endocrine disorders, like acromegaly, Cushing syndrome, hyperprolactinemia, and thyroid dysfunction. 

The diagnosis of hirsutism begins with a thorough medical history and physical exam. Medical history should focus on assessing any body changes, as well as inquiring about the individual’s menstrual history and current medications. Regarding the physical exam, excess hair growth can be quantified using the Ferriman-Gallwey score, which assesses the amount of hair present in different parts of the body. However, since the natural amount of body hair can vary between ethnic groups, the most important consideration is not necessarily the amount of body hair, but rather if the pattern of hair growth has changed or if the rate of growth has increased over time. 

Treatment for hirsutism is based on the severity of the condition and the presence of an underlying disorder. If hirsutism is caused by an underlying medical condition, treatment involves addressing the cause when possible. 

In individuals with PCOS, treatment depends on whether they have insulin resistance or desire a pregnancy. In individuals with insulin resistance who desire a pregnancy, metformin therapy and weight loss are typically recommended, as they can decrease serum testosterone levels and improve ovulation rates. Conversely, individuals without insulin resistance who do not wish to become pregnant can be treated with combined oral contraceptives (i.e., birth control pills). If oral contraceptives are contraindicated or if they are unable to treat the hirsutism, spironolactone, an aldosterone receptor antagonist which has antiandrogen effects, can be used instead.