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What Causes Excess Hair?

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Excessive hair growth, or hirsutism, can cause a great deal of distress for women. It may be associated with infertility or irregular periods with abnormal ovulation, but many times it occurs with no symptoms.

Excessive hair growth or hirsutism is different than a term called virilization. That term includes hirsutism, but also includes the development of other masculine features such as receding hairline and deepening of the voice. 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 elevation or even normal levels of testosterone.

Excess hair and hormones

The number of hairs per unit of skin is determined by heredity and ethnic back ground. There are two types of hairs: vellus hairs – short, fine light hairs that have not responded to hormones and terminal hairs – long, coarse and pigmented hairs responsive to hormones. Hypertrichosis refers to having a lot of hairs all over the body and this is common in certain ethnic groups, such as women of Mediterranean descent. This hair pattern is more generalized than hirsutism, which presents are excess hair growth in areas of face such as sideburns, lip, chin, neck, etc.

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 hair by laser hair removal is generally required.

From 25-40% of patients with hirsutism are thought to have excess androgens from both the adrenal gland and ovary, i.e., a mixed source.. Ingested sources of androgenic substances can also cause excess hair growth. This can come from supplements such as DHEA, birth control pills, and even poorly conceived nutritional supplements used to treat menopause, PMS, fatigue etc.

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.

Other causes include increased androgen sensitivity in hair follicles from: drugs (phenytoin (Dilantin®), streptomycin, hexachlorobenzene, penicillamine and diazoxide), congenital disease states (porphyria , epidermolysis bullosa, Hurler’s syndrome, trisomy E, congenital macrogingivae and Cornelia de Lange’s syndrome), acquired disease states (malnutrition due to infection or malabsorption, hypothyroidism, dermatomyositis, anorexia nervosa and head injury) and familial hypertichosis.

The sebaceous glands are even more sensitive than hair follicles to androgens (male hormones). Over stimulation of the sebaceous gland results in acne.

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.

Summary of relevant lab tests:
Thyroid Function tests
Testosterone levels
FSH, LH, Prolactin

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.