Androgenic Alopecia Flashcards
(28 cards)
What is it?
male pattern baldness— thinning in crown area normally with gradual progression to mid-scalp
- normally get decrease on side areas —- slow bald on top
What 2 factors impact the development of androgenic alopecia
1) genetic predisposition: AR gene located on X chromosome; look at mom’s dad; there is some evidence that paternal impact too
2) Androgen / test levels — higher DHT increase risk (follicular minimization )
T or F: Is the development of AA on dependent on testosterone production
F- not just test production levels that indicate development of it
— if those with androgen insensitivity syndrome —- don’t always get AA
Where are Type 1 5 alpha-reductase found
sebaceous glands, sweat glands, dermal papillae cells
Where are Type 2 5 alpha-reductase inhibitor found
outer sheath of follicle, epididymis, vas deferents, seminal vesicles + prostate
Do we want to target Type 1 or 2 5alpha reductase
Type 2
Pathogenesis of Androgenic Alopecia
- shortening of growth phase/anagen stage
- can’t keep up with the hair loss phase /telogen phase
- hairs aren’t able to grow as long +can’t keep up with hair loss
— shorter + thinner hair shaft
T or F: In androgenic alopecia, the number of hair follicles + growth cycle are completely changed
F- no change to the number of hair follicles
—- shortening of growth phase
Three Key Pathophysiologic Features of AA
1) Alterations in Hair Cycle development:: anagen phase gets shorter w/ each cycle + telogen phase remains the same
2) Follicular Minimization: decrease in size of follicle as a result of decrease vascular flow (nutrient delivery) ; likely due to high DHT
3) Inflammaiton
Formations of Minoxidil available
2% topical solution
5% foam
General admin instructions
apply to scalp BID; wait at least 4 hours before showering/getting wet
- takes 2+ mths to see benefit (up to 12 for some)
- may have increased hair loss in first 2-6 wks
If stop minoxidil, what happens
lose all hair gained in up to 3 mths
- only effective during use of drug
When to FU for effectiveness of minoxidil
6 mths
AES of minoxidil
dermatitis
increase sun sensitivity
hypertrichosis on the face
- potential CV effects: decrease in BP (vasodilator) —- caution in those with CVD (risk of systemic absorption if cut on head etc)
T or F: Oral minoxidil is also effective in helping with hair loss
T- but increase risk of AES ; generally avoid
- more CV AEs
Finasteride dosing
1mg/day
MoA: Finasteride vs Dutasteride
F: inhibits Type 2 5-alpha reductase
D: inhibit Type 1+2
- work to decrease DHT production —- minimize follicle minimization + increase length of anagen cycle
** prevent lose
Impact of finasteride on hair
lower serum level of DHT by > 60%
— lower PSA levels by 50%
improve hair thickness + pigmentation
— increase follicle size + try to normalize growth cycle
MoA: Minoxidil
vasodilator —- increase BF to stimulate more growth of hair
How long does it take to see effect with finasteride
6mths —- up to 12mth for clinically relevant effect
Once stop finasteride, how quickly do you lose your hair
6-9 mths
AEs of 5alpha-reductase inhibitors
sexual dysfxn (ED, decrease in libido)
- reduced sperm count
rare: testicular pain , depression (if over 5mg/day)
teratogenic : 1-2% can be passed in sperm
T or F: Dutasteride has official indication for androgenic alopecia
F- not officially indicated
Dose of dutasteride
0.5mg/day
- inhibits type 1 + 2 — more AEs (100X more potent to 2 and 3X more potent to type 1 ——- than F
