Hirsutism is the excessive growth of thick or dark hair in women in locations that are more typical of male hair growth patterns (eg, mustache, beard, central chest, shoulders, lower abdomen, back, inner thigh). The amount of hair growth that is considered excessive may differ depending on ethnic background and cultural interpretation.
Hypertrichosis is a separate condition. It is simply an increase in the amount of hair growth anywhere on the body. Hypertrichosis may be generalized or localized.
Men vary significantly in amount of body hair, some being quite hairy, but rarely present for medical evaluation.
Pathophysiology of Hirsutism and Hypertrichosis
Hair growth depends on the balance between androgens (eg, testosterone, dehydroepiandrosterone sulfate [DHEAS], dihydrotestosterone [DHT]) and estrogens. Androgens promote thick, dark hair growth. Testosterone stimulates hair growth in the pubic area and underarms. Dihydrotestosterone stimulates beard hair growth and scalp hair loss.
Hirsutism can be due to an
Increase in circulating androgen levels
Enhanced end organ response to androgens
Hirsutism typically results from abnormally high androgen levels as a result of increased production of androgens (eg, due to ovarian or adrenal disorders) or increased peripheral conversion of testosterone to DHT by 5-alpha-reductase. Free androgen levels also can increase as a result of decreased production of sex hormone–binding globulin, which can occur in a variety of conditions, including hyperinsulinemia, hyperprolactinemia, and in androgen excess itself. However, the severity of hirsutism does not correlate with the level of circulating androgens because of individual differences in androgen sensitivity of the hair follicle.
Hirsutism also may be the result of increased end organ response to normal plasma levels of androgens and manifest as a familial phenomenon in people of Mediterranean, South Asian, or Middle Eastern ancestry. Hirsutism in pregnancy and menopause is due to temporary, physiologic fluctuations in androgen levels.
When caused by increased androgen levels, hirsutism is often accompanied by virilization, which may manifest as loss of menses, increased muscle mass, voice deepening, acne, androgenetic alopecia, and clitoromegaly.
Hypertrichosis involves nonandrogenic hair growth.
Etiology of Hirsutism and Hypertrichosis
There are a number of causes of hirsutism (see table Some Causes of Hirsutism).
Overall, the most common cause is
Hypertrichosis is usually caused by a drug, systemic illness (see table Causes of Hypertrichosis), or paraneoplastic syndrome. It also occurs in rare familial disorders called congenital hypertrichosis.
Evaluation of Hirsutism and Hypertrichosis
History
History of present illness should cover the extent, location, and acuity of hair growth as well as the age of onset.
Review of systems should seek symptoms of virilization and review menstrual and fertility history. Symptoms of causative disorders should be sought, including polyuria (diabetes), bingeing and purging (eating disorders), and weight loss and fevers (cancer).
Past medical history should specifically seek known causative disorders such as endocrine disorders, adrenal or ovarian pathology, and cancer.
Family history should inquire about excess hair growth in family members.
Drug history should review all prescribed drugs and specifically query for the surreptitious use of anabolic steroids.
Physical examination
The presence of excess coarse and dark hair growth should be assessed at multiple sites, including the face, chest, lower abdomen, back, buttocks, and inner thigh. Signs of virilization should be sought, including
Female-pattern baldness (ie, androgenetic alopecia in women)
Acne
Increased muscle mass
Breast atrophy
Clitoromegaly
General physical examination should note signs of potentially causative disorders:
The general habitus should be examined for fat distribution (particularly a round face and accumulation of fat at the base of the neck posteriorly).
The skin should be examined for velvety, black pigmentation on the axillae and neck and under the breasts (acanthosis nigricans), and striae.
The eyes should be examined for extraocular movements and the visual fields should be assessed.
The breasts should be examined for galactorrhea.
The abdomen (including pelvic examination) should be examined for masses.
Red flags
The following findings are of particular concern:
Virilization
Abrupt appearance and rapid growth of excess hair
Pelvic or abdominal mass
Interpretation of findings
Excess hair growth beginning after use of an anabolic steroid or other causative drug (see table Causes of Hypertrichosis) in an otherwise healthy female is likely due to that drug.
Symptoms and signs sometimes point to other underlying diagnoses (see table Interpreting Findings in Hirsutism).
Abrupt onset of hirsutism or hypertrichosis may portend cancer. The abrupt onset of hirsutism may be due to adrenal, ovarian, or pituitary tumors or from ectopic hormone production from other types of tumors. Hypertrichosis lanuginosa (malignant down) is fine hair growth that appears over the entire body over a short period of time, although it can be localized to the face. It can be present in patients with several types of cancers including lymphoma and lung, breast, uterine, colorectal, and bladder cancer. Less commonly, it can be present in those with systemic diseases such as hyperthyroidism, AIDS, or undernutrition or with certain drugs.
Testing
Diagnostic testing in men with no other signs of illness is unnecessary.
Women should have laboratory measurement of serum hormone levels, including the following:
Free and total testosterone
DHEAS
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)
Depending on clinical findings, androstenedione and/or prolactin levels may also be measured.
High levels of testosterone accompanied by a normal level of DHEAS indicate that the ovaries, and not the adrenal glands, are producing the excess androgen. High levels of testosterone accompanied by moderate elevations in DHEAS suggest an adrenal origin for the hirsutism.
Often, in women with polycystic ovary syndrome, LH levels are elevated and FSH levels are depressed, which results in elevated LH/FSH ratios (> 3 is common for polycystic ovary syndrome).
Imaging
Pelvic and abdominal ultrasonography and/or CT or MRI should be done to rule out pelvic or adrenal cancer, particularly when a pelvic mass is suspected, when the total testosterone level is > 150 ng/dL (5.2 nmol/L) or > 100 ng/dL (3.5 nmol/L) in postmenopausal women, or when the DHEAS level is > 700 mcg/dL (19 micromol/L) or > 400 mcg/dL (10.8 micromol/L) in postmenopausal women. However, the majority of patients with elevated DHEAS have adrenal hyperplasia rather than adrenal carcinoma.
Patients with signs of Cushing syndrome or an adrenal mass on imaging studies should have 24-hour measurement of urine cortisol levels.
Treatment of Hirsutism and Hypertrichosis
Treatment of underlying disorder
Topical treatments
Hormonal treatment
The underlying disorder should be treated, including stopping or changing causative drugs.
Treatment for hirsutism itself is necessary only if the patient finds the excess hair cosmetically objectionable. Patients with androgen-dependent hirsutism require a combination of hair removal and antiandrogen therapy.
Nonandrogen–dependent excess hair growth, such as hypertrichosis, is treated primarily with physical hair removal methods.
Topical treatments
There are several techniques.
Epilation involves removing intact hairs with their roots and can be achieved via mechanical means (eg, tweezing, plucking, waxing) or home epilating devices. Permanent epilation techniques, including electrolysis, thermolysis, and laser epilation, can result in more long-term hair removal but often require multiple treatments.
Hormonal treatment
Hirsutism resulting from androgen excess usually requires long-term therapy because the source of excess androgen rarely can be eliminated permanently. Hormonal treatments include
Oral contraceptives
Antiandrogenic drugs
Sometimes other drugs
Oral contraceptives in standard doses often are the initial treatment for hirsutism caused by ovarian hyperandrogenism. Oral contraceptives reduce ovarian androgen secretion and increase sex hormone–binding globulin, thereby decreasing free testosterone levels.
Key Points
Hirsutism may be familial, and the degree of hair growth may vary with ethnicity.
Polycystic ovary syndrome is the most frequent cause of hirsutism.
Virilization suggests an androgenic disorder that requires further evaluation.
Abrupt onset of hirsutism or hypertrichosis may indicate cancer.
