White : Diseases of the Skin - Disorders of Hair

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Gary M. White & Neil H. Cox

Diseases of the Skin

28	Disorders of Hair

INCREASED HAIR

Hirsutism

Etiology and pathogenesis

Hirsutism may be broadly defined as excessive terminal hair in a woman in the androgen-sensitive areas. It is usually an idiopathic condition, but some cases are explained by endocrine disturbances, including polycystic ovary syndrome (PCOS), the non-classic late-onset variant of congenital adrenal hyperplasia, hyperprolactinemia, and hormone-secreting adrenal or ovarian tumors. PCOS is numerically much the most important of these. Idiopathic hirsutism is common in certain groups, for example Euro-Asian people, and some degree of hirsutism is common in postmenopausal women, due to decrease in estrogen levels.

Insulin resistance has been linked to hirsutism and occurs in 50% with PCOS. Patients with insulin resistance are more likely to be obese and to have acanthosis nigricans as well. The term HAIR-AN has been used to describe the combination of hyperandrogenism, insulin resistance, and acanthosis nigricans. Similarly, the acronym SAHA has applied to the combination of seborrhea, acne, hirsutism, and androgenetic alopecia.

Clinical

Excessive terminal hair is seen on the upper lip, cheeks, and chin in a woman with hirsutism (Figs 28.1 and 28.2). The breasts, lower abdomen, and elsewhere may also be affected.

Differential diagnosis

Although drug-induced hypertrichosis (see later) may need to be considered, the main issue is not differentiation from other disorders, but determining those patients in whom the disorder has a significant endocrine or metabolic disorder requiring intervention as compared with those in whom it is idiopathic. Clinical features that may suggest an underlying cause include:

•	abnormal menstrual cycle,
•	signs of virilization (deep voice, marked alopecia, and clitoral hypertrophy—all rare),
•	acanthosis nigricans, and
•	onset at an unusual age (most idiopathic hirsutism is apparent from teens).

The features of the main underlying causes are as follows.

•	Polycystic ovary syndrome—‘classic’ features include amenorrhea, hirsuties, infertility, and obesity, but the definition has widened to include male pattern baldness or other features of hyperandrogenism in a woman, acne, oligomenorrhea, and raised testosterone or luteinizing hormone levels.
•	Non-classic, late-onset congenital adrenal hyperplasia—usually due to 21-hydroxylase deficiency.
•	Adrenal or ovarian tumor—signs of virilization are often present (including hair loss in a ‘male pattern’), but these are rare causes of hirsutism.

Fig. 28.1Hirsutism.

Fig. 28.2 Hirsutism. It is very common for an older woman to develop significant hair growth of the upper lip as she ages.

Screening laboratory evaluation should be performed but, unless there are other symptoms, hormone levels are usually normal; for example, serum testosterone is normal in 80% of hirsute women with normal menstrual cycles. It is debatable how extensively to search for PCOS if the menstrual cycle is normal and the patient is not trying to conceive, and it is also debatable who is the best person to perform investigations; most of the identifiable causes of hirsuties are in the province of endocrinologists. Tests may include the following.

•	Ovarian ultrasound—but note that only about a third of women with polycystic ovaries fit the definition of PCOS.
•	Serum testosterone (total and free) and SHBG.
•	Androstenedione (a major precursor of testosterone in women), dehydroepiandrosterone (DHEA, usually a less significant androgen), and dehydroepiandrosterone sulfate (DHEAS) as measures of ovarian and adrenal steroid production (some measure cortisol and DHEAS).
•	Prolactin.
•	Luteinizing hormone (LH) and follicle-stimulating hormone (FSH)—a raised LH or LH:FSH ratio suggesting PCOS.
•	Glucose, lipids, and insulin (especially if acanthosis nigricans is present, but raised insulin levels, implying insulin resistance, are common in PCOS without acanthosis nigricans).

Treatment

This section describes the treatment of idiopathic hirsutism. Women with hormonal abnormalities should be referred to an endocrinologist or other appropriate specialist.

Shaving the affected areas has the fewest side effects but is usually psychologically objectionable to the patient. She should be reassured that shaving will not cause the hair to grow faster or become darker. Other treatment options include bleaching, waxing, electrolysis, depilatories, and plucking. Patients should be warned that plucking can induce ingrown hairs that mimic acne lesions.

Medical intervention includes spironolactone, cyproterone acetate combined with ethinyl estradiol (e.g. Diane or Dianette), flutamide, or finasteride (the last, however, is contraindicated in women of childbearing age due to the possibility of feminizing a male fetus). The combination of spironolactone (100mg/day) plus finasteride (5mg/day) was shown to be very effective in one study. Cimetidine also appears to be effective. Metformin is increasingly used in patients with insulin resistance and the metabolic associations of PCOS.

Topical eflornithine hydrochloride 13.9% cream is useful in ameliorating unwanted facial hair growth.

A variety of lasers can cause a permanent reduction in hair counts. Multiple treatments may produce a sustained response. The best candidates are those with light skin and dark hair. Risks of the laser include erythema and swelling, blistering, and crusting.

PRACTICE POINTS

•	The presence of hirsutism may be missed, as the appearance-conscious woman may have already treated it.
•	Ask about menstrual irregularities and infertility, and look for acne, acanthosis nigricans, and obesity in the woman with hirsutism.

Fig. 28.3 Drug-induced hypertrichosis.

Fig. 28.4 Acquired hypertrichosis lanuginosa. This woman with breast cancer developed diffuse lanugo hair after chemotherapy. Whether the cytotoxic chemotherapy or the neoplasm caused the hair growth could not be determined.

Drug-induced hypertrichosis

A small number of drugs can increase hair growth, including oral phenytoin, corticosteroids, and ciclosporin. Minoxidil, typically used as a topical agent applied to the scalp to grow hair, can rarely cause excess hair growth on the face (Fig.28.3). When given orally as a hypotensive agent, minoxidil can cause hair growth more diffusely.

Hypertrichosis lanuginosa

Etiology and pathogenesis

This may occur in both congenital and acquired forms, the latter being of importance as a manifestation of internal disease.

Hypertrichosis lanuginosa acquisita (actually a misnomer, as the hair is vellus in type) is a reliable marker of internal malignancy (e.g. of lung, colon, or breast, as well as others) (Fig.28.4). Nearly the entire body may be affected, but the face most commonly so. It is usually a late manifestation of malignancy, when the cancer is widely disseminated and the prognosis is poor.

Clinical

In hypertrichosis lanuginosa acquisita, there is sudden profuse covering of the skin by white vellus hairs. Patients may have associated weight loss, glossitis, or disturbance of taste or smell, or may have other paraneoplastic skin lesions. In the congenital form, the hair growth is present from birth and is not associated with any other symptoms.

Differential diagnosis

The differential diagnosis for increased fine or vellus hair in hypertrichosis lanuginosa acquisita, other than internal cancer, includes the following.

•	Cytotoxic chemotherapy—rarely, this may provoke the acute appearance of lanugo hair on the cheeks and neck. Approximately three-quarters of patients are women. Some patients have also had coexistent acanthosis nigricans or the sudden appearance of seborrheic keratoses..
•	Porphyrias—some types may be associated with significant facial hair, commonly on the temples. Urine (porphyria cutanea tarda) or stool (variegate porphyria) porphyrins are elevated (see Ch.17).
•	Anorexia nervosa—has been associated with increased lanugo hair..
•	Drugs—those that cause hypertrichosis usually cause terminal (dark, thick) hairs. Increased hair growth in the malar region can be an early side effect of topical use of ocular bimatoprost or latanoprost..
•	Generalized hypertrichosis with coarser hairs may occur in (usually childhood) hypothyroidism, malnutrition, and other rare circumstances..

Fig. 28.5 Hair follicle nevus. (Courtesy of O. Dale Collins III, M.D., Ph.D.)

Treatment

The malignancy should be found and treated in the acquired form. Patients can shave the hair, or use a depilatory or wax for removal.

Hypertrichotic nevi and hamartomas

Both melanocytic nevi (especially congenital nevi and those on the face) and some specifically hair-producing nevi, such as a hair follicle nevus (discussed later), may cause localized hypertrichosis. The faun tail (occurring over the sacral area; also termed lumbosacral hypertrichosis) is of particular importance, as there may be associated bony or neurologic deficit due to diastematomyelia.

Also known as simple nevoid hypertrichosis, the hair follicle nevus (Fig.28.5) represents a congenital hamartomatous increase of terminal hair follicles in a localized area. No treatment of this benign condition is needed, but surgical excision may be done.

Other localized hypertrichosis

Hypertrichosis may occur at areas of chronic inflammation, such as lichen simplex, or at the site of aluminum granulomas due to vaccines (Ch.18). Hypertrichosis may be prominent in pretibial myxedema. It is also common on a limb that has had a fracture treated with an occlusive cast.