What causes androgenetic (male pattern) alopecia and how can it be prevented?

Causes and Prevention of Androgenetic (Male Pattern) Alopecia

Androgenetic alopecia is primarily caused by genetic factors and androgens, particularly dihydrotestosterone (DHT), and can be effectively prevented or treated with FDA-approved medications like topical minoxidil and oral finasteride, which should be initiated early for optimal outcomes. 1, 2

Pathophysiology of Androgenetic Alopecia

Androgenetic alopecia (AGA), also known as male pattern hair loss (MPHL), is the most common form of hair loss affecting up to 80% of men by age 80 and 58% of men by age 50. 3, 1

The condition is characterized by:

• Progressive miniaturization of hair follicles
• Preferential hair loss affecting temples, vertex, and mid-frontal scalp in men
• Central region thinning with preserved frontal hairline in women
• Classification typically using the Hamilton-Norwood system for men and Ludwig system for women 3

Key Pathophysiological Factors:

1. Genetic predisposition - Strong hereditary component
2. Androgen activity - Particularly dihydrotestosterone (DHT), the potent form of testosterone
3. Hair follicle sensitivity to androgens, causing progressive miniaturization 1, 2

Prevention and Treatment Options

First-Line Treatments (FDA-Approved)

1. Topical Minoxidil

   • Mechanism: Potassium channel opener that promotes hair growth
   • Dosage: 5% solution applied twice daily
   • Efficacy: Superior to placebo in promoting hair growth (P<.00001)
   • Timeline: Allow 6-12 months for visible results
   • Note: Must be continued indefinitely to maintain results 4, 5

2. Oral Finasteride

   • Mechanism: 5-alpha reductase inhibitor that blocks conversion of testosterone to DHT
   • Dosage: 1mg daily for men only
   • Efficacy: Superior to placebo in promoting hair growth (P<.00001)
   • Caution: Not for use in women of childbearing potential due to risk of birth defects
   • Side effects: May cause sexual dysfunction and gynecomastia in some patients 4, 5

Adjunctive Therapies

1. Low-Level Laser Therapy (LLLT)

   • FDA-cleared treatment (HairMax LaserComb)
   • Recommended use: 3 times weekly
   • Benefits: Minimal side effects, non-pharmaceutical option
   • Efficacy: Superior to placebo in promoting hair growth (P<.00001) 4, 5

2. Platelet-Rich Plasma (PRP) Therapy

   • Recommended for mild cases or as adjunctive treatment
   • Protocol: 3-5 sessions at 4-6 week intervals, with maintenance every 6 months
   • Best for: Patients refractory to medical treatment 4, 1

3. Nutritional Considerations

   • Evaluate and correct deficiencies in:
     • Iron (particularly in women)
     • Zinc (levels below 70 μg/dL may require supplementation)
     • Vitamin D (maintain levels of at least 30 ng/mL)
     • Thyroid function 4

Treatment Algorithm

1. Early Intervention: Begin treatment at first signs of hair loss for optimal outcomes 1, 2

2. For Men:

   • First-line: Topical minoxidil 5% twice daily AND oral finasteride 1mg daily
   • Alternative/adjunctive: LLLT, PRP therapy

3. For Women:

   • First-line: Topical minoxidil 5% once daily
   • Alternative/adjunctive: LLLT, PRP therapy, oral contraceptives (if hyperandrogenism present)

4. Treatment Monitoring:

   • Take baseline photos before starting treatment
   • Evaluate progress at 3,6, and 12 months with standardized photos
   • Expect visible improvement by 6 months
   • Continue treatment indefinitely to maintain results 4

Important Considerations

• Psychological Impact: Hair loss can significantly affect self-esteem, confidence, and quality of life regardless of age or stage of baldness 6

• Treatment Expectations: While current treatments can effectively arrest progression and promote partial regrowth, complete restoration is often not possible 1

• Common Pitfalls:

  1. Delaying treatment (early intervention yields better results)
  2. Discontinuing treatment prematurely (benefits are lost when treatment stops)
  3. Expecting immediate results (treatments require 6-12 months for visible improvement)
  4. Neglecting psychological aspects of hair loss 4, 1, 6

• Hair Care Recommendations:

  • Use sulfate-free shampoos and conditioners
  • Choose hydrating formulas with natural oils and hydrolyzed proteins
  • Reduce thermal damage by limiting heat styling
  • Protect hair from environmental factors 4

By understanding the pathophysiology of androgenetic alopecia and implementing appropriate preventive and treatment strategies early, patients can effectively manage this common condition and minimize its progression.