Hair in the pubic area of infants may be benign and often resolves spontaneously by 1 year of age, especially if on the scrotum in boys and labia majora or mons in girls without other evidence of virilisation or sexual development. The terms hypertrichosis and hirsutism are frequently and inappropriately used synonymously to describe excessive hair on the body. Hirsutism implies an excessive growth of body hair in women or children (mostly girls) in an androgen-induced hair pattern (upper lip, chin, sideburn areas, neck, anterior chest, breasts, linea alba, abdomen, upper inner thighs, and legs). Hirsutism most commonly represents a physiologic variant of hair growth, often seen in several family members, which comes to medical attention only because of societal pressure to remove excessive hair. Hypertrichosis, conversely, refers to a generalized or localized pattern of non-androgen-dependent excessive hair growth in a male or female without evidence of masculinism or menstrual abnormality.
Acquired generalized hypertrichosis
Generalized hypertrichosis may be associated with neurologic disorders (post-encephalitic hypertrichosis, multiple sclerosis), anorexia nervosa, acrodynia, hypothyroidism, porphyria, dermatomyositis, gross malnutrition, and various forms of drug-induced hypertrichosis. Drug-induced hypertrichosis is most commonly seen in children who are administered phenytoin or cyclosporine, usually after 2 or 3 months of treatment, but other medications have been implicated as well. In adults, but not in children, acquired forms of hypertrichosis lanuginosa are strongly associated with internal malignancy, especially adenocarcinoma.
The original fine soft unmedullated and usually unpigmented lanugo hairs are shed in utero during the 7th or 8th month of gestation. Premature infants, however, frequently display this fine coat of lanugo hair, particularly on the face, limbs, and trunk. In these infants the fine lanugo hairs are shed during the first months of life and replaced by normal terminal hair growth, generally before the first 6 months.
Hypertrichosis lanuginosa is a rare inherited disorder in which lanugo hairs persist or are overproduced throughout life. Affected infants may be unusually hairy at birth or may develop hypertrichosis during early childhood. In some children, the hair will be spontaneously lost during childhood; in others, it will remain into adulthood. Generalized hypertrichosis can be very disfiguring. Affected children have been called ‘monkey-men,’ ‘dog-face,’ and ‘human Skye terriers’. Sporadic, autosomal recessive, and autosomal dominant cases have been described. Congenital glaucoma, skeletal abnormalities, and missing teeth have been described in association.
Ambras syndrome is a generalized condition of hypertrichosis in which the hair appears to be vellus, rather than lanugo hair. The hypertrichosis is most evident on the face, ears, and shoulders, and persists throughout life. Dysmorphic facial features have been associated. Ambras syndrome has recently been linked to a rearrangement in chromosome 8q that down regulates the expression of TRPS1 (mutated in tricho-rhino-phalangeal syndrome).
Hypertrichosis with gingival hyperplasia is a distinct autosomal dominant disorder in which affected individuals have excessive body and facial hair in an identical distribution to that of hypertrichosis lanuginosa but patients tend to have terminal hair and have associated gingival hyperplasia . Although the hypertrichosis is most commonly present at birth or in infancy, in up to half of reported cases the hypertrichosis begins at puberty. The gingival hyperplasia is usually noted with delayed tooth eruption, and has been described as pink, firm, and pebbly. The disorder is complicated by interference with chewing, respiration, and speech, and periodontal abscesses have been described because of difficulty in dental eruption. Gingival debulking may be required. A large deletion on 17q24.2–q24.3 has been found to be responsible for congenital generalized hypertrichosis, with or without gingival hyperplasia.
X-linked dominant hypertrichosis has been described in a Mexican pedigree. Affected males show excessive generalized terminal hair growth, especially on the face and upper torso; female individuals are less severely affected, and can show asymmetric hairiness thought to represent random inactivation (lyonization) of the affected chromosome. This condition sometimes improves after puberty. In another Mexican kindred, congenital universal hypertrichosis was associated with deafness and dental anomalies as an X-linked recessive disorder.
Generalized hypertrichosis is also a feature of several syndromes, most commonly, the Cornelia de Lange syndrome. This congenital disorder features marked hypertrichosis; cutis marmorata; hypoplastic genitalia, nipples, and umbilicus; growth and skeletal abnormalities; mental retardation; and a characteristic low-pitched and growling cry. The vast majority of cases are sporadic, but rare familial cases appear to be autosomal dominant. The face of afflicted individuals is characterized by overgrowth of the eyebrows, long eyelashes, high upper lip, saddle-nose, and a cyanotic hue about the eyes, nose, and mouth. Children with this disorder often have recurrent respiratory tract infections and gastrointestinal upsets; seizures have been observed in about 20% of reported cases, and most patients die before the age of 6 years. Hypertrichosis is also a feature of congenital erythropoietic porphyria
Idiopathic hirsutism describes the presence in girls of excessive body hair in a male sexual pattern (the face, particularly the upper lip, chest, abdomen, arms, and legs) in the absence of clinical evidence of disturbed endocrine or metabolic function. Idiopathic hirsutism is assumed to relate to increased stimulation of the hair follicles of genetically predisposed girls by normal levels of androgenic hormones. Hirsutism is quantified by the Ferriman–Gallwey scale, with scores of 6–8 considered mildly hirsute, 8–15 serious, and >15 overt hirsutism. Other signs of hyperandrogenism are acne, oligo- or amenorrhea, and androgenetic alopecia.
The incidence of hirsutism in any population is difficult to assess, since the range of normal is quite wide and subject to individual acceptance, and includes that which is not always socially acceptable in a particular culture. Hispanic, Jewish, and Welsh women in general have more hair than their counterparts of Northern European, Japanese, and Indian heritage. The physician should be cognizant of what is normal and acceptable to some individuals, yet unacceptable and a source of anguish to others. Performing a history and physical examination (including BMI and abdominal circumference) will determine the need for full endocrinologic investigation. When hirsutism is observed in a post-pubertal girl without other signs of masculinity (receding hairline, deepening of the voice, or evidence of menstrual disturbance), endocrine disease is unlikely. When the disorder does not appear to be physiologic and particularly if associated with other signs of androgen excess or premature puberty (sexual hair before 8 years of age in girls), abnormalities of the pituitary, adrenals, and ovaries must be ruled out. These include ‘exaggerated adrenarche’, late-onset congenital adrenal hyperplasia, virilising tumours, Cushing syndrome, hyperprolactinemia, acromegaly, Achard–Thiers (diabetes, hypertension, and hirsutism) syndrome, and polycystic ovary syndrome (PCOS)
Of these, PCOS is by far the most common and is increasing in prevalence in parallel to the increasing trend towards obesity in teenagers (3% of unselected adolescents in one study).
In addition to signs of hyperandrogenism, the presence of oligo- or amenorrhea and acanthosis nigricans is a clue to PCOS. Oligomenorrhea is defined as menstrual cycles of >35 days, with fewer than eight menstrual cycles defined as chronic anovulation. It is harder to diagnose oligomenorrhea in adolescents, but persistent irregularity more than 2 years after the onset of menses should be considered abnormal. Obesity is a significant risk factor for PCOS, and 40–60% of women with PCOS are overweight or obese, especially with abdominal adiposity.
If an endocrine abnormality is suspected, minimal laboratory testing for excessive androgen production should include levels of 17-ketosteroids (for mild adrenal hyperplasia), free plasma testosterone, dehydroepiandrosterone sulfate levels, and morning and evening cortisol; luteinizing hormone and follicle-stimulating hormone ratios and transabdominal ultrasound (to rule out small ovarian cysts) may be useful. Hormonal evaluations are best carried out in the morning during the third-fifth day of menstruation. If PCOS is suspected, fasting levels of glucose and insulin should be obtained. A recently proposed definition of PCOS in adolescents includes four of the following criteria: (1) clinical hyperandrogenemia; (2) biochemical hyperandrogenemia (serum testosterone >50 ng/dL and LH:FSH ratio of >2; (3) insulin resistance and hyperinsulinemia (acanthosis nigricans, visceral adiposity, and impaired glucose tolerance); (4) oligomenorrhea persisting 2 years after menarche; and (5) polycystic ovarian morphology on ultrasound.
Treatment of hypertrichosis and hirsutism
The appearance of excessive hair may be modified in several ways. Cutting with scissors or shaving with a razor or electric shaver, although occasionally not psychologically acceptable to the patient, are the simplest methods and least likely to irritate the skin. These techniques do not stimulate faster or thicker growth. Bleaching with hydrogen peroxide may make excessive hair less conspicuous for up to 4 weeks, and works best for light-skinned children, because yellow bleached hair may be emphasized when viewed against darkly pigmented skin. Plucking or wax epilation (essentially a form of widespread plucking) by application of a warm wax preparation to the affected areas, are too painful for children, but may be an option for older adolescents. Chemical depilatories that contain sulfides or thioglycolates, or enzymatic depilatory agents destroy the projecting hair shafts, causing minimal damage to underlying skin. Of these, the sulfide-containing preparations are more effective, but more irritating, and produce a disagreeable hydrogen sulfide odour. The thioglycolate-containing agents are less irritating but slower in action and less effective on coarse hairs. Enzymatic agents are less offensive, but not as effective as other types. Children with extensive hypertrichosis must limit treatment with chemical depilatories to localized sites because of the risk of systemic absorption and toxic reactions.
Electrolysis and laser are more permanent hair removal techniques that have not been studied and are probably too uncomfortable for pre-pubertal children. In electrolysis, an electric current is delivered to the hair follicle, destroying it. Laser and intense pulsed light therapy remove unwanted hair through the selective photothermolysis of melanin-rich structures; light energy is absorbed in hair follicles with minimal absorption by surrounding tissues. Long-pulse alexandrite and long-pulse Nd:YAG lasers have been used in lighter skin and darker skin children, respectively, for a variety of indications and with good tolerance. Application of topical anaesthesia may be required. Eflornithine cream 15% is prescription medication for twice-daily application that inhibits ornithine decarboxylase, a hair follicle enzyme that participates in hair growth. As a result eflornithine may decrease further growth, although it does not minimize existing hair. Local irritation may occur.
If an adolescent has hirsutism and hyperandrogenemia, therapy should be specific to the underlying trigger, under the guidance of a gynaecologist or endocrinologist. For example, dexamethasone 0.25–0.5 mg at night generally reverses the hyperandrogenic signs of adrenal hyperplasia. For PCOS in adolescents, the most important intervention is lifestyle modification with increasing exercise and controlling dietary intake. In PCOS, loss of at least 10% of initial body weight improves menstrual function and metabolic abnormalities. The administration of metformin or other insulin sensitizers is adjunctive to lifestyle changes, but can improve insulin resistance, adiposity and serum androgen levels. Anti-androgens and oral contraceptives are the traditional treatment for management of hirsutism. The combination of ethinyl estradiol and drospirenone, for example, reduces the Ferriman–Gallwey score in adolescents by approximately 50% over a 12-month period. Spironolactone in doses of 50–200 mg/day, cyproterone acetate, 50–100 mg/day (available in Europe), and cimetidine have anti-androgenic activity.