Chapter 61 - Lasers, Skin resurfacing, Alopecia

Question 1

3 methods of skin resurfacing

Answer 1

peel (caustic)
dermabrasion (mechanical)
laser (thermal)

Question 2

3 types of chemical peels

Answer 2

Superficial (epidermis) TCA 10-30%, Jessner, glycolic acid 40-70%, salicylic acid 5-15%
Medium (sup. dermis): TCA 35-40%, phenol 88%, combo 35% TCA w/ other agents
Deep (deep dermis): TCA 50%, baker gordon phenol peel

Question 3

Contraindications to skin resurfacing

Answer 3

facelift, medium/deep peel or laser in last 6 mo
isotretinoin past year
active HSV
active skin dz

Question 4

Two ablative lasers used in skin resurfacing

Answer 4

CO2 (10,600 nm) targets water
Er-YAG (2940 nm) also water

comparable to medium/deep chemical peels, dermabrasion

Question 5

non-ablative lasers

Answer 5

KTP (532 nm), pulsed dye (585 nm), target Hb
Nd-YAG (1064, infrared)
Intense pulsed light (IPL) (550-1200 nm), targets melanin/Hb
Fractionated CO2 (1500 nm)

Question 6

Which fitzpatrick skin types are best candidates for skin resurfacing?

Answer 6

I, II

Question 7

Makeup of Baker Gordon formula

Answer 7

88% phenol, croton oil, septisol, distilled water

depth of penetration mainly dependent on croton oil

Question 8

Hyper vs Hypopigmentation after skin resurfacing

Answer 8

Hyper: early, treat with topical tx
Hypo: later, permanent

Question 9

Phenol toxicity

Answer 9

cardiac (PVCs), hepato, nephro
individual facial subunits at 15 minute intervals
IV hydration, cardiac monitoring

Question 10

Skin changes with age

Answer 10

thinning dermis/epidermis, effacement epidermal/dermal junction, thin SQ fat, lose organization of elastic fibers and collagen
Increased laxity –> wrinkles

Question 11

Fitzpatrick classification

Answer 11

I- white/freckled...always burns
II- white...usually burns
III- white to live....sometimes burns
IV- brown...rarely burns
V- dark brown...very rarely
VI- black...never

III-VI have higher risk for pigmentary dyschromia (hyper/o) after resurfacing

Question 12

How superficial peels differ from deeper ones

Answer 12

S: exfoliate epidermis only, stimulate regeneration/thickening

Med/Deep: induce collagen production

Question 13

4 main indications for peels/dermabrasion

Answer 13

photodamage, fine wrinkles, hyper/hypo, acne scars

Question 14

Complications of peels

Answer 14

milia, pigment change, scar, dermatitis, candida infection, reactivate HSV

Question 15

Compare CO2 and Er-YAG

Answer 15

CO2: more tissue tightening

Er-YAG: energy absorbed tenfold greater, so more precise, shorter recovery/less erythema/lower pigment change risk

Question 16

How nonablative lasers work

Answer 16

dermal injury, preserve epidermis

induce fibroblast proliferation, elastin deposition in papillary dermis

Question 17

Preop tx prior to laser resurfacing

Answer 17

antiviral

avoid sun

Question 18

What is a follicular unit

Answer 18

1-4 terminal hair cells
sebaceous gland
arrector pili mm
blood
neural plexus surrounded by adventitial collagen sheath

Question 19

Hair cycle

Answer 19

Anagen (growth), catagen (involution), telogen (rest)
90-95% anagen on scalp, 1% catagen. 5-10% telogen
10-20x during lifetime

Question 20

Likely mechanism of androgenic alopecia (male pattern baldness)

Answer 20

susceptible follicles
DHT binds androgen receptor, activates genes that transform large terminal hairs into miniaturized, vellus hairs
Non-scarring
30% of 30 yo, 50% of 50 yo

Question 21

Norwood scale I - VII

Answer 21

I- Small M in front
II- larger M
III- More steep M, further posterior, plus crown
IV- Door shape (not M), more crown
V- barely any separation between crown and front
VI- no separation between crown and front
VII- lose more on sides, back

Question 22

Ludwig grades of female pattern hair loss

Answer 22

I-II from slight to obvious thinning of top of scalp…front hair line always maintained but gets progressively thinner

Question 23

When does female pattern hair loss begin?

Answer 23

As early as 20s, progresses until acceleration during menopause

Question 24

How much does androgenic alopecia advance per year without treatment?

Answer 24

5%

Question 25

2 treatments for androgenic alopecia

Answer 25

Minoxidil- vasodilator but mechanism of promoting hair growth not understood, initial surge, hair growth stops when medication stopped

Finasteride- comp INH type 2 5a-reductase…inhibits test –> DHT…does not interfere with testosterone metabolic actions

Question 26

AEs of minoxidil

Answer 26

scalp irritation, dryness, itching, redness

Question 27

AEs of finasteride

Answer 27

dec libido, erectile dysfunction, ejaculatory dysfunction

all reversible with d/c drug

Question 28

post surgical effluvium

Answer 28

sometimes hair is lost in follicular unit after transplant

will start growing again after 3-6 mo