Hirsutism & Hypertrichosis
In dermatology practice, excessive hair growth in women is often confused between two distinct conditions: hirsutism (male-pattern hair growth) and hypertrichosis (generalized or androgen-independent excess hair). Telling them apart accurately is the first step that shapes the hormonal work-up and the choice of treatment.
Hirsutism
Hirsutism is the abnormal conversion of fine vellus hair into coarse, dark terminal hair in women, in areas sensitive to male hormones (androgens) – the places where only men normally grow coarse hair after puberty (upper lip, chin, chest, linea alba of the abdomen, back, inner thighs).
At the molecular level, hirsutism depends on three key factors:
- Raised Circulating Androgens: Elevated free testosterone, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S) or androstenedione, coming from the ovaries, the adrenal glands or external sources.
- Increased 5-Alpha-Reductase Activity in the Follicle: 5-alpha-reductase (especially type 2) in the follicular infundibulum converts testosterone into DHT, which binds the androgen receptor (AR) with 5–10 times greater affinity. DHT acting on AR in the dermal papilla stimulates growth factors (such as IGF-1) that enlarge the follicle and prolong the anagen (growth) phase.
- Heightened Androgen Receptor Sensitivity: Some patients have completely normal blood androgen levels, but their hair follicles overreact to hormonal signals (idiopathic hirsutism).
Hypertrichosis
Hypertrichosis is excessive hair growth (lanugo, vellus or terminal hair) anywhere on the body. It does NOT follow a male pattern and does NOT depend on circulating androgen levels.
Hypertrichosis can affect both men and women and may be congenital or acquired:
- Congenital Hypertrichosis: Very rare and linked to inherited gene mutations (such as hypertrichosis lanuginosa congenita), in which lanugo hair fails to convert to vellus hair after birth.
- Acquired Hypertrichosis: Usually a side effect of medication (oral or topical minoxidil, cyclosporine, phenytoin, long-term corticosteroids), a metabolic disorder (porphyria cutanea tarda, malnutrition, anorexia nervosa) or a paraneoplastic sign (paraneoplastic hypertrichosis lanuginosa).
Clinical Assessment and the Modified Ferriman-Gallwey (mFG) Score
At Haute-Derma, our doctors grade hirsutism using the modified Ferriman-Gallwey score (mFG) to quantify it clinically:
- Scoring method: The doctor examines and scores 9 androgen-sensitive body areas from 0 (no terminal hair) to 4 (dense terminal hair):
- Upper lip
- Chin
- Chest
- Upper abdomen
- Lower abdomen
- Upper back
- Lower back
- Upper arms
- Inner thighs
Total mFG score = sum of the 9 areas (range 0–36)
| < 4–6 points | Normal (depending on ethnicity) |
|---|---|
| 5/6–8 points | Mild hirsutism |
| 9–15 points | Moderate hirsutism |
| > 15 points | Severe hirsutism |
- Diagnostic threshold: In Asian and Vietnamese women, a total mFG score of 5–6 is considered for a clinical diagnosis of hirsutism.
- Virilization: If hirsutism appears suddenly and progresses quickly, check right away for other signs of virilization: clitoral enlargement (clitoromegaly), a deepening voice, increased muscle mass, breast atrophy and male-pattern baldness (AGA). These are red flags for an androgen-secreting tumor of the ovary or adrenal gland.
Hirsutism vs. Hypertrichosis
| Feature | Hirsutism | Hypertrichosis |
|---|---|---|
| Sex affected | Mainly women. | Men and women equally. |
| Distribution | Androgen-sensitive areas (face, chin, chest, linea alba, back). | Generalized or anywhere (arms, legs, forehead, shoulders; not in a male pattern). |
| Androgen dependence | Yes. Increased androgen production or heightened AR sensitivity. | No. Completely independent of male hormones. |
| Main hair type | Coarse, dark terminal hair. | Vellus, lanugo or terminal hair. |
| Main causes | Polycystic ovary syndrome (PCOS > 70%), NCCAH, androgen-secreting tumors, idiopathic hirsutism. | Medications (minoxidil, cyclosporine), paraneoplastic disease, malnutrition, congenital. |
| Hormone tests | Abnormal (testosterone, DHEA-S, 17-OHP often raised). | Normal. |
| Associated signs | Acne, androgenetic hair loss (AGA), menstrual irregularities, virilization. | No androgen-related acne or menstrual irregularities. |
Investigations and Combined Treatment at Haute-Derma
Laboratory Work-Up
When the mFG score is ≥ 6, hormone tests may be ordered:
- Total and Free Testosterone: Measures overall circulating androgens. A total testosterone above 200 ng/dL (7 nmol/L) raises suspicion of an androgen-secreting ovarian tumor.
- DHEA-S (Dehydroepiandrosterone Sulfate): Assesses adrenal output. If DHEA-S is above 700 µg/dL, CT or MRI is needed to rule out an adrenocortical tumor.
- 17-Hydroxyprogesterone (17-OHP): Screens for non-classic congenital adrenal hyperplasia (NCCAH). If 17-OHP is above 2 ng/mL, an ACTH stimulation test follows.
- LH/FSH, SHBG, Prolactin, Fasting Insulin: Evaluate polycystic ovary syndrome (PCOS) and insulin resistance.
- Pelvic (Transvaginal) Ultrasound: Looks for polycystic ovaries or an ovarian tumor.
Medical Treatment
- Combined Oral Contraceptives (COC): First-line treatment for hirsutism due to PCOS. COCs containing newer progestins with strong anti-androgenic activity (drospirenone, cyproterone acetate, dienogest) are preferred. COCs suppress ovarian LH-driven androgen production and increase hepatic SHBG, lowering free testosterone.
- Anti-Androgens: Added if a COC alone has not worked after 6 months:
- Spironolactone (50–200 mg/day): Competes for the androgen receptor and inhibits 5-alpha-reductase.
- Finasteride (2.5–5 mg/day): Selectively inhibits type 2 5-alpha-reductase.
- Eflornithine 13.9% Cream: A topical inhibitor of the follicular enzyme ornithine decarboxylase (ODC) that slows facial hair growth.
- Laser and IPL Hair Removal:
- How it works: Light wavelengths (808 nm diode, 755 nm alexandrite or 1064 nm Nd:YAG) work by selective photothermolysis, targeting melanin in the hair shaft and root sheath to destroy the dermal papilla.
- Important Clinical Points in Hirsutism:
- Laser only destroys existing follicles in the anagen phase. If internal androgens are not controlled with medication, new vellus follicles will keep converting to coarse hairs and the benefit of laser will fade quickly.
- Paradoxical hypertrichosis: Thicker, coarser hair growing in nearby skin after laser or IPL (most often on the face and neck of Asian women). It happens when sub-optimal laser energy stimulates dormant vellus follicles into the anagen phase. Prevention relies on a sufficiently high fluence and active skin cooling.
