Hirsutism = excessive terminal (coarse, pigmented) hair growth in women in a male-pattern distribution (face, chest, abdomen, back, upper arms/thighs). 🚺➡️🧔 Affects ~5–10% of reproductive-age women. Main driver = ↑ androgen action at pilosebaceous unit. Often cosmetic/psychosocial distress, but important marker of underlying pathology. 😔 💡 High-yield clinical pearl: Most common cause = PCOS (>70–80% of cases). Idiopathic hirsutism next. Rare but serious = androgen-secreting tumours (red flag!).

When + virilisation (deep voice, clitoromegaly, ↑ muscle mass, male-pattern baldness) → think tumour or severe hyperandrogenism. Urgent workup! ⚠️

🔬 Pathophysiology – Understand the Mechanism 🔍

Androgen-dependent hairs convert vellus → terminal via DHT (testosterone → DHT by 5α-reductase in follicle).
Androgens from: ovaries (LH-driven) + adrenals (ACTH-driven).
Excess → terminal hair growth + ↑ sebum (acne) + virilisation in severe cases.

Mnemonic: "DHT Drives Dark Terminal Hair" 🧬

📊 Major Causes – Comparison Table (Exam Favourite!)

Cause	Prevalence / Clue	Key Clinical Features	Key Investigations	Management (Primary Care Focus)
Polycystic Ovary Syndrome (PCOS) 🌸	Most common (>70%)	Oligo/amenorrhoea, acne, obesity, infertility, acanthosis nigricans.	↑ total/free testosterone; pelvic US or AMH (per 2023 PCOS updates); exclude other causes.	Lifestyle (weight loss!); COCP first-line; add spironolactone if needed; metformin if metabolic issues.
Idiopathic Hirsutism	Common (~20–50% no endocrine disorder)	Regular cycles, gradual onset, normal androgens, no other signs.	Normal testosterone/DHEAS; diagnosis of exclusion.	Cosmetic (laser/electrolysis); topical eflornithine; consider spironolactone ± COC.
Non-classical CAH	Uncommon; early/familial	Premature pubarche, severe acne, rapid growth.	↑ basal or ACTH-stimulated 17-OHP (>10–15 nmol/L stimulated).	Glucocorticoids (e.g. prednisolone) to suppress ACTH.
Androgen-secreting tumour (ovarian/adrenal) ⚠️	Rare (<1%)	Rapid onset (<6–12 months), severe virilisation (voice, clitoris, muscle).	Very ↑ testosterone (>5 nmol/L) or DHEAS (>10–15 µmol/L); urgent US/MRI/CT.	Urgent endocrinology + surgery; oncology if malignant.
Cushing’s syndrome	Rare	Moon face, buffalo hump, striae, HTN, weakness.	↑ urinary free cortisol; dexamethasone suppression; ACTH + imaging.	Treat source (surgery); medical if inoperable.
Drugs	Uncommon	Anabolic steroids, danazol, phenytoin, minoxidil, cyclosporine.	Drug history; normal androgens if isolated.	Stop culprit; symptomatic Rx.

🩸 Quick Aetiology Summary – Memorise These! 📝

Common: PCOS ★, Idiopathic ★
Rare but red-flag: Tumour, non-classical CAH, Cushing’s
Drugs to remember: Anabolics, danazol, phenytoin, minoxidil

💡 Clinical Pearls for Exams & Wards – Must-Know! 🩺

Onset is everything: Rapid (<6–12 months) or progressive despite Rx → tumour until proven otherwise! 🚨
Virilisation = urgent referral (2-week wait) for imaging + endocrinology.
Ferriman–Gallwey score (modified): 9 androgen-sensitive sites (0–4 each, max 36). ≥8 = hirsutism in white/Black women (lower in Asian, higher in some ethnic groups). Use it! ✏️
First-line Rx (premenopausal): Combined oral contraceptive (raises SHBG, ↓ free T, ↓ LH). Ethinylestradiol-containing preferred per NICE.
Spironolactone: Androgen receptor blocker (50–200 mg/day); teratogenic → mandatory contraception; slow onset (6–12 months).
Cosmetic Rx: Laser/electrolysis best for dark hair; topical eflornithine (Vaniqa) for facial hair.
Referral triggers (NICE): Virilisation, rapid onset, testosterone >5 nmol/L, resistant to Rx, suspected tumour/CAH/Cushing’s.

📚 Key References – Cite These in Exams! 📖

NICE CKS: Hirsutism (last reviewed October 2024 – no major new evidence since).
Endocrine Society Guideline: Evaluation & Treatment of Hirsutism in Premenopausal Women (2018 – still core).
International PCOS Guideline (2023 update) – relevant for PCOS-associated hirsutism.
Williams Textbook of Endocrinology (latest ed.).

Study tip: Focus on differentiating PCOS vs tumour vs idiopathic – history + onset + androgen levels + Ferriman score will get you through most OSCEs/MCQ! Good luck! 🍀

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Hirsuitism

🧠 Introduction to Hirsutism – Key Exam Topic! 🌟

🔬 Pathophysiology – Understand the Mechanism 🔍

📊 Major Causes – Comparison Table (Exam Favourite!)

🩸 Quick Aetiology Summary – Memorise These! 📝

💡 Clinical Pearls for Exams & Wards – Must-Know! 🩺

📚 Key References – Cite These in Exams! 📖

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