Hirsutism is defined as the excessive growth of thick dark hair in an androgen-dependent pattern where hair growth in women is usually minimal or absent, such as the face, chest and areolae. This is different from hypertrichosis, which refers to excess hair in areas that are not androgen dependent.
Hirsutism is a common and often distressing condition. It affects 5-10 per cent of all women. It is more common in dark-haired women and also in obese women.
Hirsutism is a symptom rather than a disease and may be a sign of a more serious medical condition, especially if it develops after puberty.
Hirsutism occurs as a result of either increased androgen production or an increased sensitivity of hair follicles to androgens, or both. Overproduction of androgens results in an increased hair follicle size, hair fibre diameter and duration of time hair follicles spend in the anagen (growth) phase.
The distribution of hair in women with high androgen levels is also altered. Excessive hair growth occurs in androgen-sensitive regions, but hair loss occurs on the scalp.
The most common causes of clinical hyperandrogenism are polycystic ovary syndrome (around 72 per cent of women) and idiopathic hirsutism (around 23 per cent of women).
Other causes include late-onset adrenal hyperplasia, Cushing's syndrome, androgen-secreting tumours, acromegaly, insulin resistance and hypothyroidism.
Some drugs can cause hirsutism, for example anabolic steroids, metoclopramide, phenothiazines and progestogens.
Idiopathic hirsutism is common and is often familial. It is usually a diagnosis of exclusion and usually first presents shortly after puberty. It progresses slowly and there are no other signs of virilism. Menstruation is normal, as are any investigations.
In menopausal women, a reduction in ovarian estradiol occurs. Testosterone production is relatively stable though and this can lead to an increase in hair growth.
In some women, increasing levels of luteinizing hormone can cause stromal hyperplasia with high testosterone levels, which then leads to hirsutism.
The severity of hirsutism does not correlate directly with the level of increased circulating androgens because of individual differences in conversion to 5-alpha-reductase and androgen sensitivity of hair follicles.
Although there is a scoring system, that can be used to measure hair growth (Ferriman and Gallwey), this is usually only used for research purposes.
Subjective assessment is usually adequate for women presenting with hirsutism.
Any recent onset and rapid progression of hair growth should be noted as this can occur with the rare androgen-secreting tumours.
Other signs of virilism should be documented. The patient should be asked about any changes in her menstrual cycle and also any medication, including the oral contraceptive pill.
For many women who present with idiopathic hirsutism, further investigations are unnecessary.
The initial laboratory investigations include TFTs and measurement of free androgen index, prolactin, 17-hydroxyprogesterone and 24-hour urine cortisol (to rule out Cushing's syndrome if suspected).
Pregnancy should be ruled out in women with 'irregular' or absent menstrual cycles.
Testosterone measurement is only needed for women with moderate to severe hirsutism. It is not essential in all women with hirsutism.
Obese women with polycystic ovary syndrome should have an oral glucose tolerance test and cholesterol test performed.
Patients with either menstrual disturbances or clinical evidence of hyperandrogenism should have a pelvic ultrasound to look for polycystic ovaries.
The following women should be considered for referral to secondary care:
- If the hirsutism is severe.
- If hair growth is of recent onset and rapid progression.
- If firstand second-line treatments have not been effective over six to 12 months or if the hair growth worsens despite treatment.
- If the serum testosterone concentration is more than twice the normal range.
- If the presence of a metabolic syndrome requires a multidisciplinary approach.
The decision to start treatment will vary depending on the woman's perception of her condition and how much it impacts on her quality of life. Weight loss should be encouraged in women with hirsutism who are overweight or obese.
Treatment will take around four months before any benefit is seen. This is because hair grows in cycles, and it can take months for an individual hair follicle to proceed through catagen, anagen and telogen phases.
All systemic treatments reduce stimulation of the anagen growth phase by testosterone, and enough follicles have to pass through anagen before a clinically obvious effect is seen.
Hair removal methods, for example, waxing, shaving or threading, do not exacerbate hair growth. Electrolysis and laser epilation or photoepilation are often used successfully. However, these treatments may cause folliculitis, skin irritation, scarring and pigmentary changes.
Eflornithine cream acts as a growth inhibitor. It inhibits the enzyme ornithine decarboxylase, which is required for hair growth.
It should be used twice a day for at least four to eight weeks and should be stopped if no benefit is seen within four months of starting.
It is recommended that eflornithine is given if combined oral contraceptives are contraindicated or do not work. It is contraindicated during pregnancy and breastfeeding.
Co-cyprindiol or a combined oral contraceptive pill containing drospirenone may be given.
A co-cyprindiol pill is licensed for the treatment of moderately-severe hirsutism but it should be stopped three or four menstrual cycles after hirsutism has resolved.
Although the drospirenone and ethinylestradiol contraceptive pill is not licensed specifically for this use, it is often given for women who require long-term treatment.
Women should be advised that it may take up to six months for a benefit to be seen with systemic treatment.
Treatments in secondary care include anti-androgens (cyproterone acetate, spironolactone); 5-alpha-reductase inhibitors (finasteride); insulin-sensitising drugs (metformin) and gonadotropin-releasing hormone analogues (goserelin and leuprorelin).
These drugs are not licensed for the treatment of hirsutism and can have serious adverse effects, so it is recommended that they should only be used under specialist supervision.
- Dr Newson is a GP in the West Midlands
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