Hirsutism — GP Clinical Algorithm
Excess terminal hair growth in androgen-dependent distribution · NICE CKS · Endocrine Society 2018
Progress0 / 9
The full reasoning pathway — most hirsutism is PCOS, but rapid onset or virilisation with a high testosterone signals an androgen-secreting tumour. Treat, support, and safety-net.StartDecisionInvestigateActionReferStop / Admit
PresentationHirsutism
Onset/speed, distribution (Ferriman-Gallwey), menstrual history, virilisation. Examine; measure testosterone, SHBG.
Step 8 · Lifestyle & treatment optionsPCOS-focused, takes months to work
Weight loss improves androgen levels, cycles and metabolic risk in PCOS. Cosmetic measures (shaving, waxing, laser/electrolysis, topical eflornithine) + COCP ± anti-androgen (e.g. co-cyprindiol) — set expectations that hair response takes ≥6 months. Address mood/self-esteem. Screen and manage cardiometabolic risk in PCOS.
Step 9 · review & safety-net
Step 9 · Review & safety-netReassess response & red flags
Review at ~6 months for treatment response (slow); escalate or refer if inadequate. Urgent for any rapid progression, new virilisation (voice change, clitoromegaly, balding) or testosterone >5 nmol/L → tumour work-up. Confirm contraception with anti-androgens (teratogenic), and reassess the diagnosis if the picture is atypical.
⚠️ Rapid virilisation is a tumour until proven otherwise: a markedly raised testosterone or fast-onset masculinisation needs urgent investigation, not a trial of the pill.
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Safety · Red Flags
Identify features requiring urgent action
Refer same day / urgently to endocrinology or gynaecology if any of the following are present:
Rapid onset / progressionVirilisation developing over weeks–months suggests tumour
Virilisation featuresClitoromegaly, voice deepening, temporal balding, breast atrophy
Very high testosteroneTotal testosterone >5 nmol/L raises suspicion of ovarian/adrenal tumour
Acanthosis nigricans + obesitySevere insulin resistance syndrome; screen for diabetes
Prepubertal / postmenopausal onsetNew hirsutism outside reproductive years warrants investigation
Androgen-secreting ovarian tumours (e.g. Sertoli–Leydig cell) and adrenal tumours are rare but dangerous causes. Testosterone >5 nmol/L has a high positive predictive value. The Endocrine Society 2018 guideline recommends urgent referral for rapid virilisation (Azziz et al., JCEM 2018). Cushing's syndrome, though uncommon, causes significant morbidity if missed.
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Diagnose · History
Focused history
Onset & rate
Gradual (years) → PCOS or idiopathic. Rapid (months) → tumour
Menstrual history
Oligomenorrhoea / amenorrhoea → PCOS or thyroid/prolactin disorder
Family history
Ethnic background (Mediterranean, South Asian); familial hirsutism
Influences treatment choice (COCP vs metformin vs clomifene)
Weight / BMI change
Weight gain worsens hyperandrogenism in PCOS via insulin resistance
Skin symptoms
Acne, seborrhoea, alopecia — other androgen-excess features
Symptoms of Cushing's
Weight gain, mood change, weakness, easy bruising
Score hair distribution using the modified Ferriman–Gallwey (mFG) score — 9 body sites scored 0–4; mFG ≥ 8 defines hirsutism in most populations (threshold varies by ethnicity).
The mFG score is the standard validated tool (Ferriman & Gallwey 1961; modified by Hatch 1981). Endocrine Society recommends mFG ≥ 8 as the diagnostic threshold, though this varies by ethnicity — East Asian women may be affected at lower scores (Azziz et al. 2018). Drug causes are more common than often recognised and should be excluded before investigation.
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Diagnose · Examination
Clinical examination
BMI & waist
Obesity (BMI >30) and waist >88 cm increase risk of metabolic complications in PCOS
Moon face, buffalo hump, central obesity, proximal weakness, purple striae
Pelvic exam
Consider if adnexal mass suspected (ovarian tumour)
Acanthosis nigricans is a clinical marker of insulin resistance and is present in 50–70% of women with PCOS and obesity (Dunaif 1997). Clitoromegaly is a key virilisation sign that strongly suggests androgen-secreting tumour or exogenous androgen use. Central obesity with striae should prompt 24-hour urinary cortisol or overnight dexamethasone suppression test for Cushing's.
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Diagnose · Investigations
First-line blood tests
Take bloods in early follicular phase (days 1–5) if menstruating, or any time if oligomenorrhoeic/amenorrhoeic:
Elevated in adrenal androgen excess; very high (>18 µmol/L) → adrenal tumour
Pelvic ultrasound: If PCOS suspected — ≥20 antral follicles per ovary OR ovarian volume >10 mL (Rotterdam criteria 2018 update).
PCOS is diagnosed by Rotterdam criteria (2003, updated 2018): 2 of 3 features — oligo/anovulation, clinical/biochemical androgen excess, polycystic ovaries on USS. NICE CKS Hirsutism (2023) recommends testosterone, SHBG, LH, FSH, prolactin, and TSH as first-line. 17-OHP screens for non-classical congenital adrenal hyperplasia (21-hydroxylase deficiency), which accounts for ~5% of hirsutism. DHEAS elevation points to adrenal rather than ovarian androgen source (Azziz et al. 2018).
1 mg overnight dexamethasone suppression test or 24-hr urinary free cortisol if clinically suspected.
Drug-induced
Medication review
Anabolic steroids, danazol, phenytoin, minoxidil, ciclosporin. Stop/switch if possible.
PCOS is the most common cause of androgen excess in reproductive-age women (Azziz et al., NEJM 2006). Idiopathic hirsutism (normal androgens, regular cycles) has a prevalence of ~5–15% and results from peripheral androgen sensitivity (5α-reductase type 1 activity in pilosebaceous units). Late-onset (non-classical) CAH due to 21-hydroxylase deficiency is found in ~2–8% of hirsute women and is diagnosed by ACTH-stimulated 17-OHP (Speiser et al., JCEM 2010).
Suspected Cushing's syndrome or adrenocortical tumour
Routine Endocrinology
Late-onset CAH confirmed (17-OHP >6 nmol/L) for genetic counselling and treatment
Routine Gynaecology / Repro medicine
PCOS with infertility or if COCP contraindicated and fertility desired
Consider Dermatology
Idiopathic hirsutism unresponsive to 6 months' pharmacological treatment
GP manage
Mild–moderate PCOS or idiopathic hirsutism with no virilisation — manage in primary care
NICE CKS (2023) states that most women with mild–moderate hirsutism and confirmed PCOS or idiopathic hirsutism can be managed in primary care. Urgent referral is necessary when androgen-secreting tumour or Cushing's is suspected — delay risks malignant progression and significant morbidity. Infertility in PCOS requires specialist ovulation induction (clomifene, letrozole, gonadotrophins or surgical).
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Treat · Pharmacological
Pharmacological management
Allow 6 months before assessing treatment response — hair cycle is slow.
1st lineCombined oral contraceptive pill (COCP) — preferred if contraception also desired. Reduces ovarian androgen production and raises SHBG. Any COCP is effective; those with anti-androgenic progestogens (drospirenone, cyproterone acetate) may offer modest additional benefit. ⚠ Cyproterone acetate carries meningioma risk — minimise duration; not beyond 5 years if possible (MHRA 2020)
Add / 2nd lineAnti-androgens — consider if COCP insufficient after 6 months:
• Spironolactone 25–100 mg/day — blocks androgen receptor; requires effective contraception (teratogenic). Monitor potassium and BP.
• Finasteride 2.5–5 mg/day — 5α-reductase inhibitor; off-label; teratogenic — use only with reliable contraception.
• Flutamide — effective but hepatotoxic; rarely used now.
PCOS ± insulin resistanceMetformin 500–2000 mg/day — reduces insulin, lowers LH/androgens; also improves cycle regularity and aids weight loss in obese PCOS. Not primarily anti-hirsutism but reduces progression.
TopicalEflornithine 11.5% cream (Vaniqa®) — inhibits ornithine decarboxylase in hair follicles; slows facial hair growth. Applied BD; response in 8–16 weeks. Effect reversible on stopping. Licensed for facial hirsutism in women ≥18 years.
All systemic anti-androgen treatments are teratogenic — reliable contraception is mandatory throughout.
RCT evidence supports COCP as first-line (van Zuuren et al., Cochrane 2015 — 167 RCTs reviewed). Spironolactone (25–100 mg) reduces mFG by ~40% in RCTs. Eflornithine reduces hair growth by ~30% vs placebo in two pivotal RCTs (Balfour & McClellan 2001). MHRA (2020) issued a warning about cyproterone acetate and meningioma risk after French pharmacoepidemiology study showed 6–7× relative risk at cumulative doses >36 mg. Metformin alone is not an effective hirsutism treatment but reduces progression via insulin sensitisation (Tang et al., BMJ 2012).
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Lifestyle · Cosmetic
Non-pharmacological & cosmetic measures
🏃 Weight loss (if obese)5–10% weight reduction in obese PCOS women reduces androgen levels by ~15%, improves menstrual regularity, and enhances treatment response. Mediterranean diet + aerobic exercise recommended.
✂️ Cosmetic hair removalShaving, threading, waxing, depilatory creams — safe and effective short-term. Does NOT increase hair growth (myth). Important while awaiting pharmacological response.
⚡ Laser / IPL therapyEffective for long-term hair reduction on dark hair. Multiple sessions needed. Laser (Nd:YAG, diode) licensed for hirsutism — referral to dermatology or specialist. NHS availability varies.
⚡ ElectrolysisPermanent hair removal — only method proven permanent. Time-intensive; suitable for small areas. NHS rarely funds.
🧠 Psychological supportHirsutism significantly impacts quality of life, self-esteem, and mental health. Acknowledge distress, avoid dismissiveness. Consider CBT or psychological referral in severe cases.
🚭 Medication reviewStop or switch causative drugs where clinically safe (e.g. minoxidil → alternative antihypertensive; danazol for endometriosis → alternative).
Weight loss in obese PCOS women reduces insulin resistance, lowering LH and androgen levels (Kiddy et al. 1992; Moran et al. 2011 systematic review). NICE CKS (2023) and BFS guidelines emphasise that cosmetic measures are an important complement to medical treatment, not inferior alternatives. A systematic review (Lipton et al. 2006) found that hirsutism significantly impairs body image and self-esteem. Laser hair removal is effective for darker hair with fair skin; Nd:YAG is safer for darker skin phototypes (Fitzpatrick IV–VI).
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Safety · Follow-up
Monitoring, safety-netting & follow-up
6-month review
Reassess mFG score and patient satisfaction after at least 6 months of treatment (one hair cycle)
COCP monitoring
Annual BP; review meningioma risk if using cyproterone-containing COCP — reassess at 5 years
Spironolactone
Check U&E and BP at 4–6 weeks then annually; avoid in renal impairment; use effective contraception
Metformin
eGFR before starting; annual HbA1c and lipids in PCOS; B12 if long-term use
PCOS long-term
Annual screening: BP, weight, HbA1c/fasting glucose, lipids; risk of T2DM (~7× increased) and cardiovascular disease
Menstrual regularity
Induce withdrawal bleeds ≥every 3–4 months if amenorrhoeic (endometrial hyperplasia risk); COCP or progestogen
Safety-net
Return if: hair growth accelerates, new virilisation features, mood change on COCP, or irregular bleeding on treatment
Fertility planning
If contraception stopped and pregnancy desired, refer for ovulation induction. Lifestyle optimisation first.
Women with PCOS have a 7-fold increased risk of type 2 diabetes and 2–3× increased cardiovascular risk (Wild et al. 2010). Unopposed oestrogen from chronic anovulation raises endometrial cancer risk — NICE PCOS guidelines (NG88 2023) recommend inducing bleeds every 3–4 months. mFG scoring at follow-up provides objective outcome measure. Spironolactone hyperkalaemia is rare in young healthy women but requires monitoring, especially at doses >100 mg (Mackay & Kaviani 2021 review).
References: NICE CKS Hirsutism (2023) · NICE NG88 PCOS (2023) · Endocrine Society Hirsutism Guideline — Azziz et al., JCEM 2018 · Rotterdam ESHRE/ASRM PCOS Consensus 2003/2018 · van Zuuren et al., Cochrane 2015 · MHRA Cyproterone Acetate Safety Review 2020 · Speiser et al. (CAH), JCEM 2010 For educational use only. Always apply clinical judgement and local guidelines.