CausesBy Mayo Clinic staff
Until puberty, your body is covered with fine, colorless hairs called vellus hairs. When you begin to sexually mature, male sex hormones called androgens help vellus hairs on certain areas of your body become dark, curlier and coarser hairs called terminal hairs. Unwanted terminal hair growth in women (hirsutism) can result from excess androgens or from an increased sensitivity of hair follicles to androgens.
About half the women with mild hirsutism have high androgen levels. Hirsutism that's severe is usually due to high androgen levels. Conditions that can cause high androgen levels include:
- Polycystic ovary syndrome. This common condition is caused by an imbalance of sex hormones that may result in irregular periods, obesity, infertility and sometimes multiple cysts on your ovaries. Polycystic ovary syndrome is the most common identifiable cause of hirsutism.
- Cushing's syndrome. Cushing's syndrome is a condition that occurs when your body is exposed to high levels of the hormone cortisol, a steroid hormone involved in your body's response to stress. It can develop when your adrenal glands — small hormone-secreting glands located just above your kidneys — make too much cortisol, or it can occur from taking cortisol-like medications over a long period. Increased cortisol levels disrupt the balance of sex hormones in your body, which can result in hirsutism.
- Congenital adrenal hyperplasia. This inherited condition is characterized by abnormal production of steroid hormones, including cortisol and androgen, by your adrenal glands.
- Tumors. Rarely, an androgen-secreting tumor in the ovaries or adrenal glands may cause hirsutism.
- Medications. Some medications can cause hirsutism. One such drug is danazol, which is used to treat women with endometriosis.
Sometimes, no identifiable cause
Excessive hair growth in women with normal androgen levels, regular menstrual periods and no other underlying conditions is called idiopathic hirsutism — meaning that there's no identifiable cause of the disorder. This occurs more frequently in certain ethnic populations, such as women of Mediterranean, Middle Eastern and South Asian ancestry.
- Evaluation and treatment of hirsutism in premenopausal women: An Endocrine Society clinical practice guideline. Chevy Chase, Md.: The Endocrine Society. http://www.endo-society.org/custom_apps/search.cfm?q=hirsutism. Accessed Oct. 29, 2010.
- Chang J, et al., eds. The Hormone Foundation's patient guide to the evaluation and treatment of hirsutism in premenopausal women. The Hormone Foundation. http://www.hormone.org/Resources/Patient_Guides/upload/Hirsutism_Patient_Guide.pdf. Accessed Oct. 29, 2010.
- Hirsutism. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merck.com/mmpe/sec10/ch124/ch124c.html?qt=hirsutism&alt=sh#sec10-ch124-ch124c-989. Accessed Oct. 29, 2010.