Androgenic Alopecia

Aka: Androgenic Alopecia, Androgenetic Alopecia, Male-patterned Baldness

1. See Also
   1. Alopecia
2. Definition
   1. Non-scarring androgen related Alopecia
3. Epidemiology
   1. Most common type of Alopecia (esp. white men)
   2. Hereditary trait (positive Family History)
   3. Increasing Incidence with age
      1. Affects white men 30% at age 30, 40% at age 40, 50% at age 50 years
      2. Affects 38% of women over age 70 years
4. Course
   1. Hair Loss onset between ages 12 to 40 years
   2. Hair Loss evident by age 50 in >50% of patients
5. Pathophysiology
   1. Androgen exposure shortens Hair FollicleAnagen phase
      1. Men with increased androgen levels
      2. Women with increased 5a-reductase, androgen receptors
   2. Affected hair becomes shorter, finer, less pigmented
   3. Progresses with each successive cycle
   4. Related to higher Dihydrotestosterone (DHT) levels
      1. Metabolite of testosterone
6. Symptoms
   1. Gradual progression of Hair Loss
7. Signs
   1. Men (M-Type distribution)
      1. Hair Loss affecting temples, frontal forehead and crown (vertex)
      2. Sides and back are spared
   2. Women
      1. Central and vertex scalp thinning
      2. Temples and frontal scalp are spared unlike the M-Type found in men
8. Differential Diagnosis
   1. Hypothyroidism
   2. Iron Deficiency Anemia
   3. Malnutrition
9. Grading: Rating of Hair Loss (Norwood and Hamilton Scale)
   1. Type I: Minimal hair line recession
   2. Type II: Symmetrical triangular Hair Loss over temples
   3. Type III: More Hair Loss at vertex and less at temple
   4. Type IV-V: Temple and vertex Hair Loss; some crown loss
   5. Type VI: Contiguous frontal, vertex, and crown baldness
   6. Type VII: Hair remains only over ears and occiput
   7. References
      1. Hamilton (1951) Ann NY Acad Dermatol 53:708-28
      2. Norwood (1975) South Med J 68(11):1359-65 [PubMed]
10. Labs: Women with Androgenetic Alopecia
    1. Indications (Not required in most cases)
       1. Irregular Menses
       2. Sudden Hair Loss
       3. Hirsutism
       4. New onset Acne Vulgaris
       5. Infertility
    2. Lab tests
       1. Total Testosterone
       2. Free Testosterone
       3. Dehydroepiandrosterone sulfate (DHEA-S)
       4. Prolactin
11. Management
    1. Precautions
       1. Medications used for Alopecia are continued indefinitely (Hair Loss recurrs with med discontinuation)
    2. Medications for women
       1. Minoxidil (Rogaine) 2%
          1. Applied topically twice daily to dry scalp
          2. Risk of Hypertrichosis of the face
          3. Retin-A may augment effect (experimental)
             1. Apply at different time of day
       2. Oral Contraceptives
          1. Less effective than Minoxidil
          2. Choose OCP with low Progestin Androgenic Activity
             1. Norgestimate (e.g. Ortho Tri-Cyclen)
             2. Norethindrone (e.g. Modicon)
       3. Spironolactone
          1. Variable efficacy - results in modest reduction in Hair Loss
          2. Dose: 100 to 200 mg orally daily in divided doses
       4. Flutamide (Eulexin)
          1. Dose: 250 mg orally daily
          2. Liver function abnormalities occur in up to one third of patients
       5. Finasteride is ineffective in women
    3. Medications for men
       1. Finasteride (Propecia)
          1. Dose: 1 mg orally daily
             1. Consider prescribing one quarter tablet daily of the 5 mg tablet (generic, cheap)
          2. Indicated for men only, and if topical Minoxidil ineffective
          3. Oral preparation for vertex or frontal balding
          4. Modifies serum PSA levels (upper limit of normal may be twice that of those not on Finasteride)
          5. May help detect high grade Prostate Cancers earlier
             1. Thompson (2003) N Engl J Med 349:215-24 [PubMed]
       2. Minoxidil (Rogaine) 2% solution or 5% foam
          1. Most effective for vertex balding (than in frontal area), and effects are delayed 6-12 months
          2. Applied topically (1 ml) twice daily to dry scalp
       3. Ketoconazole 2% Shampoo (Nizoral)
          1. Shampoo 2-4 times weekly
          2. Unknown efficacy and not FDA approved for Androgenetic Alopecia
       4. Pyrithione Zinc (1%)
          1. Shampoo 2-4 times weekly
          2. Unknown efficacy and not FDA approved for Androgenetic Alopecia
    4. Hair Transplant
       1. Looks better in photos
       2. Better in curly haired persons
    5. Avoid ineffective or unproven measures
       1. Avoid topical oils
       2. Avoid oral supplements for Alopecia (Biotin, keratin, Saw Palmetto, zinc)
12. References
    1. Drake (1996) J Am Acad Dermatol 35:465-9 [PubMed]
    2. Phillips (2017) Am Fam Physician 96(6): 371-8 [PubMed]
    3. Scow (1999) Am Fam Physician, 59(8):2189-94 [PubMed]
    4. Springer (2003) Am Fam Physician 68(1):93-102 [PubMed]