Hirsutism and hyperandrogenism

Definition

Differentiating the Terms

• Hirsutism: terminal hair at androgen-dependent sites.
• Hypertrichosis: androgen-independent hair growth, often drug-induced.
• Virilisation: hirsutism plus clitoromegaly, voice deepening.
• How hirsutism is graded: using the Ferriman-Gallwey score (9 body regions).
• What rapid progression with virilisation means: suspicion of androgen-producing tumor (urgent workup!).

• Hirsutism is excessive growth of thick, dark hair in a male pattern in women after puberty, for example in the beard and moustache area, on the chest, back, lower abdomen and inner thighs.
• It results from raised circulating androgen levels or increased androgen sensitivity of the hair follicles; severity therefore does not correlate closely with androgen levels.

Occurrence & epidemiology

Epidemiology

• Hirsutism is common and is estimated to affect nearly 10% of women in the United States; what is considered excessive depends on ethnic background and cultural perception.

Aetiopathogenesis

Aetiology and pathogenesis

• The most common cause is polycystic ovary syndrome.
• Non-classic congenital adrenal hyperplasia is almost always due to 21-hydroxylase deficiency with increased production of 17-hydroxyprogesterone and androstenedione and may clinically resemble PCOS.
• Androgen-secreting ovarian and adrenal tumours are rare causes; they typically cause rapidly progressive hirsutism later in life, adrenal carcinomas often together with Cushing syndrome.
• Further causes include Cushing syndrome, acromegaly, hyperprolactinaemia, ovarian hyperthecosis and androgenic substances such as anabolic agents.
• Idiopathic hirsutism, with normal androgen levels, regular menses and no identifiable cause, is a diagnosis of exclusion; it is found in about half of women with mild hirsutism.

Clinical features

• Acne, menstrual irregularities and androgenetic alopecia are often associated; acanthosis nigricans points to hyperinsulinaemia, for example in PCOS.
• Abrupt onset, rapid progression, onset later in life or signs of virilisation such as clitoromegaly, deepening of the voice, increased muscle mass and male-pattern baldness point to an androgen-secreting tumour.

Diagnosis

Laboratory Tests

• Basic parameters: total testosterone, SHBG, DHEAS, androstenedione.
• Why SHBG is also measured: to estimate free, biologically active testosterone.
• What lowers SHBG levels: obesity and insulin resistance (increases free T.).
• A markedly elevated DHEAS points to: to an adrenal cause.
• To rule out adrenogenital syndrome: 17-hydroxyprogesterone (early follicular phase).

• Severity is quantified with the Ferriman-Gallwey score, which rates nine androgen-sensitive body areas from 0 to 4 each.
• Baseline tests include free and total testosterone, DHEAS, LH and FSH, plus prolactin if menses are irregular; 17-hydroxyprogesterone is measured if congenital adrenal hyperplasia is suspected.
• High testosterone with normal DHEAS suggests an ovarian source, and additionally raised DHEAS an adrenal source.

Keep learning in the app

Further reading (selection)

1. StatPearls: Hirsutism (NCBI Bookshelf)
2. MSD Manual Professional: Hirsutism and Hypertrichosis
3. Endocrine evaluation of hirsutism (Int J Womens Dermatol 2017, PubMed Central)
4. DocCheck Flexikon, Hirsutismus

Cross-references