What is the recommended approach to investigate and treat androgenic alopecia in women?

Investigation and Treatment of Androgenetic Alopecia in Women

For women with androgenetic alopecia, a thorough diagnostic workup should be performed, including laboratory evaluation for hormonal abnormalities, followed by treatment with topical minoxidil as first-line therapy, with oral antiandrogens as second-line options for those with signs of hyperandrogenism. 1, 2

Diagnostic Approach

Clinical Assessment

• Evaluate pattern of hair loss: diffuse thinning at the crown with maintenance of frontal hairline (Ludwig pattern) 3
• Assess for signs of hyperandrogenism: hirsutism, acne, irregular menstrual cycles 3
• Determine onset, progression, and family history of hair loss

Trichoscopy (Scalp Dermoscopy)

Trichoscopy is essential for diagnosis and should reveal:

• Hair shaft diameter diversity (>20% variability)
• Increased proportion of vellus hairs (>1.5:1 ratio frontal:occipital)
• Yellow dots in frontal area (more prominent in advanced cases)
• Perifollicular discoloration
• Decreased mean hair thickness in frontal area 4

Laboratory Investigations

For women with androgenetic alopecia, particularly those with signs of hyperandrogenism, the following tests should be performed:

1. Hormonal Panel:

   • Free and total testosterone
   • DHEA-S (dehydroepiandrosterone sulfate)
   • Androstenedione
   • Luteinizing hormone (LH)
   • Follicle-stimulating hormone (FSH) 5

2. Additional Tests:

   • Thyroid function tests (TSH, free T4)
   • Complete blood count
   • Serum ferritin (to assess iron stores)
   • Vitamin D levels
   • Zinc levels (preferably morning samples) 1

Pitfall: Laboratory evaluation is not recommended for all patients with androgenetic alopecia but should be performed in women who have additional signs of androgen excess such as hirsutism, acne, or irregular menses 5.

Treatment Options

First-Line Treatment

• Topical minoxidil 2% or 5% applied twice daily to dry scalp
  • Mechanism: Prolongs anagen phase and increases hair follicle size
  • Efficacy: Significantly superior to placebo in promoting hair growth in women 6
  • Side effects: Local irritation, hypertrichosis on face if solution runs down

Second-Line Treatments

For women with signs of hyperandrogenism or those not responding to minoxidil:

1. Antiandrogen Therapy:

   • Spironolactone (50-200 mg daily)

     • Contraindicated in pregnancy due to risk of feminization of male fetus
     • Monitor potassium levels

   • Low-dose oral combination therapy:

     • Minoxidil 0.25 mg + spironolactone 25 mg once daily 1

2. 5-alpha reductase inhibitors:

   • Finasteride (1-5 mg daily)
     • Less effective in women than men unless hyperandrogenism is present
     • Absolutely contraindicated in pregnancy (Category X)
     • Pregnant women should not handle crushed tablets 1, 2

Adjunctive Therapies

• Low-level laser therapy (3 times weekly)

  • FDA-cleared for androgenetic alopecia
  • Minimal side effects 1, 6

• Platelet-rich plasma (PRP) therapy

  • Initial phase: 3 sessions at 4-6 week intervals
  • Maintenance: Every 6 months 1

• Nutritional supplements (if deficiencies are present):

  • Iron (if ferritin <70 μg/dL)
  • Vitamin D (maintain levels >30 ng/mL)
  • Zinc 1

Monitoring and Follow-up

• Evaluate treatment response at 3 months
• Significant improvements should be noticeable by 6 months
• Comprehensive evaluation at 12 months to decide on continuing or modifying treatment 1
• Document progress with standardized photography

Special Considerations

• Rule out other causes of hair loss that may mimic androgenetic alopecia:

  • Telogen effluvium
  • Early scarring alopecia
  • Alopecia areata (diffuse pattern)
  • Systemic lupus erythematosus 5

• In premenopausal women with sudden onset or rapidly progressive hair loss, consider polycystic ovarian syndrome (PCOS) as a potential cause 3

Important: Androgenetic alopecia is a chronic progressive condition that requires long-term treatment. Patients should be counseled that the goal of therapy is primarily to prevent further hair loss and secondarily to promote regrowth 7, 2.