How does Polycystic Ovary Syndrome (PCOS) cause hirsutism and acne, and can metformin help manage these symptoms?

PCOS-Related Hirsutism and Acne: Pathophysiology and Metformin's Role

Metformin can help manage hirsutism and acne in PCOS by improving insulin sensitivity, which indirectly reduces androgen levels, though it is generally less effective than combined oral contraceptives for these specific symptoms.

Pathophysiology of Hirsutism and Acne in PCOS

PCOS causes hirsutism and acne through androgen excess, which occurs through several mechanisms:

• Insulin resistance leads to compensatory hyperinsulinemia, which:

  • Stimulates ovarian androgen production
  • Decreases sex hormone binding globulin (SHBG) production in the liver
  • Results in higher levels of free circulating androgens 1

• Elevated androgens directly affect hair follicles and sebaceous glands:

  • Convert vellus hair to terminal hair in androgen-sensitive areas (face, chest, abdomen)
  • Increase sebum production in the skin
  • Promote follicular hyperkeratinization and bacterial colonization, leading to acne 2

Effectiveness of Metformin for Hirsutism and Acne

Hirsutism Management

• Metformin alone:

  • Shows moderate efficacy for hirsutism by improving insulin sensitivity
  • May reduce Ferriman-Gallwey hirsutism scores 3
  • Works primarily by reducing insulin resistance rather than directly suppressing androgens 3
  • Takes 6+ months to show visible improvement 4

• Comparative effectiveness:

  • Less effective than combined oral contraceptives (COCs) for hirsutism in women with BMI 25-30 kg/m² 5
  • Similar effectiveness to COCs in women with BMI <25 kg/m² or >30 kg/m² 5
  • Most effective when combined with COCs rather than used alone 5

Acne Management

• Metformin can improve acne in PCOS patients:

  • Reduced acne prevalence from 36% to 4% in one study 4
  • Works by improving insulin sensitivity and indirectly reducing androgen levels
  • May take several months to show significant improvement

• Guidelines recommend:

  • Topical treatments (benzoyl peroxide, retinoids) as first-line for mild acne 2
  • Combined approaches for moderate-severe acne 2
  • Endocrinologic evaluation for patients with acne and additional signs of androgen excess 2

Treatment Approach for PCOS-Related Hirsutism and Acne

First-line Options

1. Combined oral contraceptives (COCs):

   • Most effective first-line therapy for both hirsutism and acne 1, 6
   • Suppress ovarian androgen production
   • Increase SHBG, reducing free testosterone
   • Provide endometrial protection

2. Metformin:

   • Dosage: Start at 500 mg daily, increase to 1000-1500 mg/day in divided doses 1
   • Best for PCOS patients with metabolic features (insulin resistance, obesity)
   • May be used as monotherapy or in combination with COCs
   • Takes longer to show effects compared to COCs

Second-line Options

1. Anti-androgens (when COCs contraindicated or ineffective):

   • Spironolactone 100 mg daily for hirsutism 1
   • Requires 6+ months for visible improvement

2. Combination therapy:

   • Metformin + COCs shows superior results for hirsutism compared to either alone 5
   • Consider in patients with severe symptoms or inadequate response to monotherapy

Adjunctive Measures for Hirsutism

• Hair removal methods are essential as medications only prevent new hair growth:
  • Laser therapy or electrolysis for permanent reduction 6
  • Enhanced results when combined with metformin in PCOS patients 7

Important Considerations

• Timeframe for improvement:

  • Hirsutism: Minimum 6 months to see improvement
  • Acne: May respond more quickly (2-3 months)

• Side effects:

  • Metformin: Higher risk of gastrointestinal side effects compared to COCs 5
  • COCs: Higher risk of other adverse events (headaches, mood changes, VTE risk) 5

• Monitoring:

  • Regular follow-up every 6 months to assess response and adjust treatment 1
  • Monitor for metabolic parameters, menstrual cycles, and symptom improvement

Conclusion

For PCOS patients with hirsutism and acne, the treatment approach should be based on symptom severity, metabolic features, and contraindications. While metformin can help manage these symptoms by improving insulin sensitivity and indirectly reducing androgen levels, it is generally less effective than COCs when used alone. The combination of metformin with COCs provides superior results for both hirsutism and acne in PCOS patients.