(also see the related topic of PCOS)
Thomas Higgins, M.D.
Hirsutism is the development of androgen-dependent terminal body hair in a woman in places in which terminal hair is normally not found. Terminal body hairs are the stiff, pigmented hairs normally seen in men on the face, chest, abdomen, and back, and which are not normal in women. A woman's definition of hirsutism may differ depending upon her ethnic background and upon her interpretation of normal, which is often influenced by popular images of hairless female beauty.
Any definition of normal body hair must take into consideration race and ethnicity. Most Asian and Native American women have little body hair, while Mediterranean women on average have moderately heavy body hair. The most important consideration, whatever the woman's background, is whether the pattern of hair growth has changed or the rate of growth has increased.
There are two conditions characterized by generalized hair growth that do not represent true hirsutism:
Androgen-independent hair, which is the soft, vellus, unpigmented hair that covers the entire body. In infants, this hair is called lanugo.
Hypertrichosis, which refers to diffusely increased total body hair. This is a rare condition that is usually caused by a drug or systemic illnesses. Rarely hypertrichosis is idiopathic.
Causes of Hirsuitism
The most common causes of hirsuitism are idiopathic hirsutism and polycystic ovary syndrome. The distinction between idiopathic disease and the polycystic ovary syndrome may be one of degree and some consider idiopathic hirsuitism to be a mild form of PCOS.
Idiopathic hirsutism: The diagnosis of idiopathic hirsutism is given to women with hirsutism and no other clinical abnormalities. The serum androgen concentrations in these women are more often within the normal range than are the concentrations in women with definable causes of hirsutism.
Polycystic ovary syndrome: The polycystic ovary syndrome is the most common cause of androgen excess in women. The minimum criteria for this diagnosis are:
- Menstrual irregularity
- Evidence of hyperandrogenism
- Exclusion of other disorders such as congenital adrenal hyperplasia and androgen-secreting tumors
In general, the symptoms of both idiopathic hirsuitism & PCOS begin around puberty and gradually worsen with age.
Less common causes of hirsutism:
- Drugs: Danazol and the androgenic progestins present in some oral contraceptives such as norgestrel (contained in Ovral) can cause hirsutism.
- Hyperprolactinemia: Should be considered in patients with hirsuitism and ameorrhea plus a breast discharge.
- Congenital adrenal hyperplasia: Excess androgen production is a key feature of most forms of congenital adrenal hyperplasia. These disorders are usually recognized at birth or in early infancy, but late-onset (also called non-classical) forms of several of them have been identified. Affected women present peripubertally with hirsutism and sometimes menstrual irregularity or primary amenorrhea.
- Hyperthecosis: Hyperthecosis is a nonmalignant ovarian leading to increased serum testosterone concentrations. It is still unclear if hyperthecosis is a distinct disorder or is part of the spectrum of the polycystic ovary syndrome. The woman's history usually is one of gradual onset of hirsutism and other manifestations of androgen excess. Most women with ovarian hyperthecosis are obese and have a long-standing history of hirsutism that is usually severe. Unlike PCOS, which occurs only during the reproductive years, hyperthecosis of the ovaries can occur in postmenopausal women.
- Ovarian tumors: Hirsutism caused by an androgen-secreting tumor is most likely to occur later in life and progress more rapidly than when the cause is the polycystic ovary syndrome. Many of these tumors can be identified by vaginal ultrasonography.
- Adrenal tumors: Adrenal tumors are a rare cause of androgen excess.
- Severe insulin resistance syndromes: Women who have one of the syndromes of severe insulin resistance and marked hyperinsulinemia often have hirsutism.
These causes represent less than 5% of all cases of hirsuitism but should be suspected in older women and women who develop hirsutism rapidly.
Most physicians recommend some laboratory evaluation for many but not all women with hirsutism. The tests that provide the most useful information are measurements of serum testosterone, prolactin, and DHEA. DHEA-S is almost entirely derived from the adrenal gland whereas testosterone, in hirsute women, is mostly secreted by the ovary.
- Serum testosterone: The serum testosterone concentration is the single best test for evaluating hirsuitism. The upper limit of normal for serum testosterone in women varies from 60 to 80 ng/dL. Values below 150 ng/dL exclude ovarian and adrenal tumors. These values also tend to exclude ovarian hyperthecosis where the serum total testosterone is usually greater than 200 ng/dL. Most women with the PCOS have serum testosterone concentrations below 150 ng/dL. Women with idiopathic hirsutism are even more likely to have normal values.
- Serum prolactin: Serum prolactin should be measured because an occasional woman with hirsutism and irregular menstrual cycles may have hyperprolactinemia due to hypothalamic disease or a pituitary tumor.
- Serum DHEA-S: Serum DHEA-S should be measured in women with rapidly progressing hirsutism and in those who are virilized in an attempt to detect an adrenal tumor. The secretion of DHEA-S begins to fall after age 20 years; as a result, serum DHEA-S measurements must be interpreted according to age-specific normal ranges. Serum DHEA-S concentrations are normal or slightly increased in most women with androgen excess. Values above 500 µg/dL suggest the presence of an adrenal tumor.
Treatment of Hirsutism
Therapy is usually continued indefinitely because increased androgen production or sensitivity is life-long. However, many women find that the balance between treatment and cosmetic concerns changes as they get older and elect to stop treatment.
In obese women, weight loss can reduce androgen production and therefore slow hair growth.
Hair removal: Physical methods of removing hair or making it less visible can be effective and their use should be encouraged either alone or as a supplement to drug therapy.
Women should be warned not to expect an improvement until after at least three to six months of therapy. In addition, all currently available medications for hirsutism need to be stopped when a pregnancy is desired.
Oral Contraceptives: Oral contraceptives slow hair growth in between 60 and 100 percent of hyperandrogenic women and are generally considered first-line therapy. Therapy should be begun with a formulation that contains a low dose of estrogen and a nonandrogenic progestin.
Antiandrogen Therapy: Antiandrogens are an effective treatment for hirsutism. They should not be administered without an oral contraceptive to women who are sexually active. In the United States, spironolactone is the only antiandrogen approved for hirsutism. The usual dose of spironolactone is 50 to 100 mg twice daily, but the effect is dose-related and larger doses are sometimes required. The drug appears to be effective in 60 to 70 percent of women. The side effects of spironolactone include hyperkalemia, gastrointestinal discomfort, and irregular menstrual bleeding, which can be managed by addition of an oral contraceptive.
Other drugs effective in the treatment of hirsuitism include:
- Cyproterone acetate
- Gonadotropin-releasing hormone agonist
Idiopathic hirsutism and PCOS are the major causes of hirsuitism. Neither is a life threatening disorder. However, they are not usually reversible and the cumulative effect of chronic androgen excess typically causes a gradual increase in hair growth with age if untreated.
Hirsutism can be effectively treated in many women with nonpharmacologic methods and an oral contraceptive, assuming that they do not wish to become pregnant. It is important to counsel the woman that it may take three to four months for a decrease in hair growth to become evident, if it occurs at all. Women who wish to become pregnant should not initiate medical therapy for hirsutism.
With time, some women may decide that daily drug treatment is no longer worth the effort for the cosmetic benefit they obtain and elect to stop treatment.
Serious underlying causes of hirsuitism can be suspected by atypical age of onset, rapid progression, more severe physical findings and laboratory determination.