What is the recommended workup and treatment for a premenopausal woman with progressive crown and frontal scalp thinning consistent with female pattern hair loss, without other scalp disease, recent severe illness, or medication changes?

Management of Female Pattern Hair Loss

For a premenopausal woman with progressive crown and frontal scalp thinning consistent with female pattern hair loss, initiate treatment with topical minoxidil 5% twice daily and perform mandatory endocrine evaluation to assess for androgen excess. 1, 2

Clinical Diagnosis

Pattern Recognition:

• Look for the characteristic Ludwig pattern (central scalp thinning with preserved frontal hairline) or the "Christmas tree pattern" (frontal accentuation with triangular-shaped thinning wider in the frontal scalp). 1, 3, 2
• Examine for miniaturized hairs using dermoscopy—this is a hallmark finding that confirms the diagnosis. 1, 4
• The scalp should appear normal without inflammatory scaling; if scaling is present, consider seborrheic dermatitis as a separate condition. 1
• Absence of patchy loss and exclamation mark hairs distinguishes this from alopecia areata, which requires entirely different treatment (intralesional corticosteroids). 5, 1

Mandatory Laboratory Workup

Endocrine evaluation is mandatory in all patients with female pattern hair loss, even when isolated FPHL without clinical hyperandrogenism is present: 1, 2

• Androgen assessment: Free and total testosterone, DHEA-S (dehydroepiandrosterone sulfate), and androstenedione. 1
• Additional recommended testing: TSH and free T4 to rule out thyroid disease, serum ferritin, vitamin D, zinc levels, and prolactin if menstrual irregularities are present. 1, 2

The most common endocrinological abnormality associated with FPHL is polycystic ovarian syndrome (PCOS). 3 However, isolated FPHL should not be considered a sign of hyperandrogenism when androgen levels are normal. 2

First-Line Treatment Algorithm

For women without hyperandrogenism:

• Start with topical minoxidil 5% solution, 1 mL applied twice daily to the affected scalp. 1, 2, 6 This is the only FDA-approved treatment for female pattern hair loss and should be applied for a minimum of 12 months. 3
• Treatment must be continued indefinitely—hair loss will return to pretreatment status if therapy is discontinued. 1

For optimal results, consider adding platelet-rich plasma (PRP):

• PRP combined with minoxidil produces the highest increase in hair density compared to either treatment alone. 1
• Initial treatment phase: 3-5 sessions spaced exactly 1 month apart using 5-7 mL PRP, injected at 90-degree angle, 2-4 mm depth, 1 cm apart in areas of hair loss. 5, 1
• Maintenance phase: 1 session every 6 months. 5, 1

Treatment for Severe Hair Loss or Hyperandrogenism

Add antiandrogen therapy when there is severe hair loss or documented hyperandrogenism: 2, 6

• Spironolactone is the most commonly used oral antiandrogen, typically at doses of 100-200 mg daily. 7, 8, 6
• Cyproterone acetate is an alternative antiandrogen option. 8, 6
• 5α-reductase inhibitors (finasteride) can be considered, though evidence is stronger in men. 2, 8
• Combination therapy with spironolactone and minoxidil has documented additive effects, with further hair regrowth observed when minoxidil is added to spironolactone monotherapy. 7

Monitoring Treatment Response

Schedule formal evaluation at specific intervals: 1

• 3 months initially for minoxidil alone to assess tolerance and early response.
• 12 months for comprehensive assessment, especially with PRP combination therapy.

Use objective measures to assess response: 1

• Standardized before-and-after photographs taken under identical lighting conditions.
• Trichoscopy to measure hair density per cm² and hair shaft diameter.
• Hair pull tests to assess the proportion of telogen hairs.
• Patient self-assessment questionnaires for satisfaction scores.

Positive response indicators include: 1

• Increased hair density per cm²
• Increased hair shaft diameter
• Decreased proportion of telogen hairs
• Improved patient satisfaction scores

Critical Pitfalls to Avoid

• Never stop treatment prematurely—treatments work best when initiated early and arrest progression rather than stimulate dramatic regrowth. 8, 6
• Do not delay effective treatment with unproven supplements (like saw palmetto, which lacks robust high-quality data), as this may result in irreversible hair loss. 5
• Avoid inadequate follow-up—patients need regular monitoring to assess response and maintain treatment adherence. 1
• Do not overlook the psychological impact—FPHL causes significant psychological distress and impaired social functioning in affected women; consider counseling and cosmetic camouflage options. 1, 8, 6

Advanced Treatment Options

For inadequate response to medical therapy:

• Hair transplantation (follicular unit extraction) can be considered for selected cases of severe FPHL with well-preserved occipital donor area. 5, 8, 6
• PRP can be used as an adjunct to hair transplantation with pre-treatment and follicle soaking to improve outcomes. 5
• Hair systems provide immediate cosmetic benefit but are rarely natural-appearing. 5