Evaluation of Excessive Hair Growth (Hirsutism)

Frederick R. Jelovsek MD

Excessive hair growth (hirsutism) in women is usually an undesirable symptom. It can often be associated with infertility or irregular menstruation due to anovulation, but many times it occurs with no menstrual or ovulatory disturbance. Excessive hair growth can make a women take on masculine features but it is different than a medical term called virilization. That term is used to include hirsutism, but also to include the development of further masculine features such as receding hairline, deepening of the voice development of male-type pubic hair and enlargement of the clitoris. Almost always, virilization in a female is caused by very high levels of male hormones such as testosterone, whereas hirsutism may be associated more with milder levels of "male-hormone" elevation or even normal levels.

This week we look at the educational bulletin published by the American College of Obstetricians and Gynecologists (ACOG) entitled Evaluation and Treatment of Hirsute Women. No 203, Mar 1995 and see what questions it can answer about increased hair growth in women.

If I have a lot of hair on my body, does that mean I have too much male hormone in my system?

The number of hairs per unit of skin is fixed by heredity. Where and how many sweat gland and hair follicle units (pilosebaceous) you have is determined by your ethnic back ground. There are two types of hairs,

• vellus hairs - short, fine nonpigmented hairs that have not responded to hormones
• terminal hairs - long, coarse and pigmented hairs responsive to hormonal influence

If genetically you have a lot of hairs all over your arms and legs, such as in women of Mediterranean background, this is called hypertrichosis. It is not due to too many hormones but is just the way you were born.

Excess androgen hormones make terminal hairs heavier and thicker. Sometimes they can also make the fine vellus hairs convert to terminal hairs. Once the vellus hairs convert, lowering the hormonal levels will not make them go back to fine, vellus hairs. Once that happens, removal of the entire pilosebaceous unit by dilapatory creams, electrolysis or laser heating is the only way stop the excess growth.

What are the hormonal factors that control hair growth?

The sebaceous gland associated with most hairs is actually more sensitive to androgens (male-type) hormones than is the hair follicle. Hyperstimulation of the sebaceous gland accompanied by bacterial infection results in acne and rarely, in an extreme, chronic infection called hidradenitis suppurativa. The endocrinologic factors that influence the pilosebaceous unit are:

• the rate and amount of androgen secretion by the ovary and adrenal gland
• the blood concentration of sex hormone binding globulin (SHBG)
• conversion in the fat cells and skin of weak, less potent androgens, to potent androgens
• sensitivity of the pilosebaceous unit to androgens

Excess androgens can be secreted by ovarian or adrenal hyperfunction such as polycystic ovarian disease or adrenal hyperplasia, or there may be independent hormone secreting tumors of the ovary or adrenal gland. Sex hormone binding globulin, if increased in amount by estrogens can neutralize free testosterone by "binding" it to an inactive form. Conversely, if estrogens are low in the blood, more testosterone is unbound and is free to stimulate hair growth. There is a more potent form of androgen than testosterone called dihydrotestosterone (DHT) which is much more effective at stimulation hair growth and acne formation.

What is the cause of excessive hair growth in women?

Assuming that heavy hair growth is not just your own genetic make-up, hirsutism can be caused by several different factors and the best treatment to reverse the excess hair growth depends upon which of those factors are working in your specific case.

• altered androgen metabolism (conversion from weak to potent androgens) - this is the most common cause of hirsutism and it appears to be the result of an increased conversion in the skin of testosterone to DHT.
• increased androgen production - either the ovary (testosterone) or the adrenal gland (dehydroepiandrosterone sulfate - DHEA-S) can be responsible for excess androgens. The adrenal gland is less common but there are several recognized genetic instances in which the adrenal gland over produces androgens.
• decreased androgen binding in the circulation - only free androgen is biologically active. Estrogens increase liver manufacture of SHBG. Androgens decrease it. Thus lack of estrogens can effectively increase available blood androgens. Also any ingestion of androgens by mouth will further decrease SHBG and make those ingested androgens even more available to stimulate hair growth.
• exogenous androgens - medications such as Estratest®, danazol, anabolic steroids in some of the body building supplements and even some birth control pills containing norgestrel (e.g., Lo-Ovral®, Ovrette®) can cause increased hair growth. Even when testosterone cream is used on the vulva for certain vulvar skin conditions, there can be absorption into the blood stream which stimulates hair growth.

What lab studies or hormonal tests are needed to diagnose the cause of hirsutism?

Doctors usually order blood levels of testosterone, to check out an ovarian source and DHEA-S to check out an adrenal source of excess androgens. If both studies show levels in normal range, treatment is directed toward reducing the available androgens in blood circulation.

If the testosterone is over 200 ng/dL an ovarian ultrasound is used to look for a functioning ovarian tumor. If DHEA-S is over 700 mcgm/dL, an MRI is ordered to rule out and adrenal tumor. If the DHEA-S is between 500 - 700 mcgm/dL, then further endocrine testing is needed to rule out adrenal hyperfunction such as hyperplasia.

Two other hormonal tests, prolactin and 17-OH progesterone may also be ordered especially if the excess hair growth has been present since puberty, there is a strong family history of hirsutism, ethnic background is Ashkenazi Jewish, a woman is shorter than other family members or there is evidence of defeminization such as a decrease in breast size. These risk factors can be associated with genetic causes of adrenal hirsutism that do not always result in elevated DHEA-S levels.

What can be done to decrease excess hair growth?

The treatment to decrease hair growth depends, of course, on what the cause is. If a tumor of the ovary or adrenal gland is found, it should be surgically removed. If there is just hyperfunction of the ovary or adrenal gland, then hormonal suppression of that hyperfunction is the treatment of choice. For ovarian hyperfunction, birth control pills or any regimen that blocks ovulation is used. For adrenal hyperfunction, dexamethasone is often used to block the excess androgen secretion. If there is ingestion or application of exogenous androgens, they should be stopped or at least lowered in dose.

The majority of the cases and sometimes the most difficult treatment situation is when the androgens are at normal blood levels. In this case treatment is directed at reducing more potent androgens (DHT) or decreasing the available free androgens. The former may be treated with inhibitors of the testosterone conversion to DHT such as flutamide. Even the herbal remedy, saw palmetto, may be useful in this regard. Estrogens in birth control pills or menopausal supplemental levels are used to increase SHBG. Finally, spironolactone, a diuretic, has some usefulness in treating hirsutism. It inhibits some enzymes important in androgen synthesis and directly competes at the level of the androgen receptor in the hair cell to block testosterone or DHT. Low dose oral contraceptives and spironolactone at 100-200mg per day are often prescribed together for hirsutism if there is no evidence of an independent source of elevated androgens.

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