Updated Diagnosis and Treatment of Androgenetic Alopecia
Diagnosis
Androgenetic alopecia (AGA) diagnosis relies on clinical pattern recognition combined with dermoscopic evaluation, which has become the standard diagnostic tool. 1
Clinical Patterns
- Male pattern: Bitemporal recession of the frontal hairline followed by diffuse thinning at the vertex (Norwood-Hamilton classification) 1
- Female pattern: Diffuse thinning of the crown region with maintenance of the frontal hairline (Ludwig pattern) 1
Dermoscopic Evaluation
- Scalp dermoscopy should be performed routinely as it facilitates diagnosis, allows differential diagnosis with other conditions, enables severity staging, and monitors disease progression and treatment response 1
- Key dermoscopic findings include progressive reduction in hair diameter, length, and pigmentation 1
Important Diagnostic Considerations
- In premenopausal women, AGA may indicate hyperandrogenism and should prompt evaluation for associated hirsutism and acne 1
- Exclude other causes of hair loss including medication-induced alopecia, nutritional deficiencies (iron deficiency, excess vitamin A), hypothyroidism, chemotherapy, and scarring alopecia 2
First-Line Treatment
Topical minoxidil 5% applied twice daily is the FDA-approved first-line treatment and must be continued indefinitely, as discontinuation reverses hair growth benefits. 3, 2
Minoxidil Protocol
- Dosing: Apply 1 mL of 5% minoxidil solution to the entire affected scalp twice daily 2, 4
- Timeline for results: Hair regrowth may be seen as early as 2 months, but most patients require at least 4 months of continuous use to see results 2
- Initial shedding: Expect temporary increased hair loss for up to 2 weeks when starting treatment—this indicates shedding of old hairs to make way for new growth 2
- Long-term efficacy: Hair regrowth has been demonstrated to last up to 48 weeks in clinical trials with continuous treatment 2
Minoxidil Efficacy and Tolerability
- In clinical studies with men aged 18-49 years with moderate hair loss, 5% minoxidil provided more hair regrowth than 2% minoxidil 2
- Both male and female patients show improvement after 6 months of treatment, with efficacy confirmed by global photography and videodermoscopy 5
- Common side effects include scalp greasiness, mild itching, and rare contact sensitization 5
- Women may develop facial hair growth with 5% formulation 2
Advanced Combination Therapy
The combination of topical minoxidil 5% with topical finasteride 0.25% demonstrates significantly superior efficacy compared to either monotherapy and represents the most effective medical treatment approach. 3, 6
Combination Protocol (Minoxidil + Finasteride)
- Apply 5% minoxidil in the morning and 0.25% finasteride spray in the evening 6
- This combination showed +81 hair density/cm² increase at 6 months compared to baseline (p < 0.001) 6
- 79% of patients achieved a global photographic assessment score ≥2 at 6 months, compared to only 8% with finasteride alone and 41% with minoxidil alone 6
- The combination works through complementary mechanisms: minoxidil stimulates follicles while finasteride blocks DHT production 6
Topical Finasteride Advantages
- Topical finasteride 0.25% daily demonstrates efficacy with less marked decrease in serum DHT levels compared to oral intake, potentially reducing systemic side effects 7
- Good tolerability with comparable safety profile to monotherapies 6
Platelet-Rich Plasma (PRP) Therapy
PRP combined with topical minoxidil is significantly more effective than minoxidil monotherapy and should be considered for patients seeking enhanced results. 3, 8
PRP Treatment Protocol
- Initial phase: Three treatment sessions spaced one month apart 3, 8
- Maintenance phase: One session every 6 months 3
- Injection technique: Use 5-7 mL of PRP at a rate of 0.05 to 0.1 mL/cm², with injections at 1 cm intervals and depth of 2-4 mm 3
- Anesthesia: Strongly recommend pharmaceutical-grade anesthetic cream due to injection pain 3
PRP Efficacy
- PRP increases hair density by 27.7-45.9/cm² compared to baseline 8
- Combined PRP with minoxidil therapy increases hair density 1.74 times and hair diameter 14.3 times 8
- Higher platelet concentrations result in greater improvements in hair density, follicle diameter, and terminal hair density 8
- Non-activated PRP shows greater increase in hair count and total hair density (31%) compared to activated PRP 8
Important PRP Considerations
- Evidence quality caveat: While multiple studies show benefit, protocols vary widely and standardization is lacking 8
- Patients with mild AGA respond better than those with severe, long-standing disease 8
- A 25% improvement in hair density at 2 months predicts sustained response at 6 months 8
Platelet-Rich Fibrin (PRF) as Alternative
PRF represents a promising alternative to PRP with theoretical advantages including longer growth factor release, though high-quality comparative studies are lacking. 8, 3
PRF Protocol
- Treatment schedule: 3-5 sessions at 1-month intervals 3
- Maintenance: One session every 6 months 3
- PRF is safe, easy, time and cost-effective with patient satisfaction scores of 7.42/10 8
- PRF shows particular efficacy in mild AGA cases 8
PRF Advantages Over PRP
- Functions as both scaffold and reservoir for growth factors with prolonged release 8
- May be more cost-effective than PRP 8
- Shows statistical improvement across all ages, genders, and AGA severity grades 8
Critical limitation: No randomized controlled trials comparing PRF directly to PRP exist as of 2023 8
Monitoring Treatment Response
Evaluate treatment efficacy using multiple objective and subjective methods at regular intervals. 3
Assessment Methods
- Standardized before-and-after photographs at baseline, 3 months, and 6 months 3
- Trichoscopy to evaluate hair density and diameter changes 3
- Hair pull tests to assess hair fragility 8
- Patient self-assessment questionnaires for satisfaction and subjective improvement 3
Key Response Indicators
- Increased hair density and shaft diameter 3
- Decreased proportion of telogen (resting phase) hairs 8
- Improved patient satisfaction scores 3
- Negative hair pull test after treatment (83% of patients) 8
Emerging and Alternative Treatments
Oral Minoxidil
- Initial dose of 2.5 mg daily, frequently increased to 5 mg daily for male hair loss 7
- Main adverse effect is hypertrichosis, with less common dizziness or lower limb edema 7
- Not FDA-approved for AGA but shows effectiveness in clinical studies 7
Low-Level Laser Therapy (LLLT)
- Wavelengths between 630-660 nm demonstrate efficacy 7
- Recommended usage three times per week 3
- Can be used at home for 15-30 minutes daily 7
- Limited evidence comparing efficacy to other medical options 7
Dutasteride
- Oral dutasteride 0.5 mg induces better responses than finasteride, especially in the frontal area 7
- Mesotherapy with dutasteride is increasingly used, though evidence is limited to retrospective studies 7
Critical Treatment Pitfalls to Avoid
- Discontinuing treatment prematurely: Patients must understand that stopping minoxidil reverses all benefits 3, 2
- Inadequate follow-up: Failure to monitor treatment response leads to suboptimal outcomes 3
- Expecting immediate results: Set realistic expectations that visible improvement requires 2-4 months minimum 2
- Ignoring the initial shedding phase: Patients may discontinue treatment during the normal 2-week shedding period if not properly counseled 2
- Using 5% minoxidil in women: Women should use 2% formulation to avoid facial hair growth 2
- Treating without proper diagnosis: Ensure AGA is the correct diagnosis and exclude other treatable causes of hair loss 2, 1