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Describe changes seen in aging skin.
- The majority of age-dependent changes that occur in our skin happen in the dermis, which can lose from 20-80% of its thickness as a result of changes in the fibroblasts, decreasing production of collagen, elastin and glycosaminoglycan (GAG).
- Hyperpigmentation spots due to erratic melanocyte activity from cumulative Ultraviolet (UV) exposure.
- Wrinkles due to reduction in muscle mass and skin thickness, cross-linking of collagen and elastin in the dermis, and dehydration of the Stratum Corneum (SC).
Describe skin care after chemical peel.
Care: sunscreen for 3 months, emollients for moisture, resume topical tretinoin
Describe the post-op healing time after chemical peel
- 5 days: epidermis regenerates
- 1 week: epidermis loosely attached to dermis
- 2 weeks: new collagen deposits, youthful look
- 1 mo: pigment returns
- 6 mo: epidermis normalizes
- 10 mo: dermis normalizes
What are the indications for a retinoic acid peel?
- corrects epidermal dysplasia, reduces actinic keratosis, increases vascularization, disperses melanin granules
- relatively mild effect, can enhance other peels
- safe to do at home
Indications for a trichloroacetic acid (TCA) peel?
- superficial and medium depth peel
- concentrations >45% can cause scarring
- coagulation necrosis to the papillary dermisless effective than phenol, but less risk of hypopigmentation
Depth of penetration of the phenol peel (Bakers Solution is 88% phenol)?
- liquefaction necrosis causing deep dermal injury
- middle reticular dermis
- tape occlusion for deeper penetration
Advantanges and disadvantages of a phenol peel (Bakers Solution is 88% phenol)?
- advantages: effective for severe pigmented lesions and wrinkles
- disadvantages: systemic effects, requiring preoperative evaluation of cardiac, renal, and liver function.
- Hydrate preoperatively, avoid treating large patches
Describe the Fitzpatrick scale
- I: white, pale, freckled
- II: white, pale with beige tint
- III: white to light brown
- IV: light to moderate brown
- V: medium to dark brown
- VI: dark brown/black
During phenol peel, describe strategies to avoid complications
- hydrate preoperatively
- don't peel more than 25% of the face
- wait 10 minutes between peels
What is the role of treatment with tretinoin and hydroquinone before and after chemical peels?
- Tretinoin qHS for 2-4 weeks preop for medium to deep chemical peels. It speeds up epidermal healing, and increase the depth of the chemical peel by decreasing the thickness of the stratum corneum. Post-op until reepithelialization is complete and maturation of the skin is complete, usually around 3 months.
- 4-8% hydroquinone: Fitzpatrick level III or greater and patients treated for melasma, the use of 4-8% hydroquinone gel may reduce hyperpigmenation.
What factors determine power density when using laser?
power (watts) divided by spot size (area)
Two days after CO2 laser resurfacing, your patient complains of painful “blisters” around her mouth. What is the likely diagnosis? How will you treat her?
- HSV activation, can diagnose with Tzanck smear
- valacyclovir 500 mg BID x 7d
- purulence may indicate staph superinfection
Describe the role of CO2 laser in skin resurfacing.
- primarily absorbed by water
- 20-60 um depth of penetration on first pass
- reepithelialization in 8d, erythema for 3-6 mo
- hypopigmentation is most common complication
Describe the role of Erbium:YAG laser in skin resurfacing.
- absorbed by water (12-18x CO2)
- 3-5 um depth of penetration
- reepithelialization in 5d, erythema for 3-4 weeks
- less collagen remodeling and tightening than CO2 laser
Describe the role of Nd:YAG laser in skin resurfacing.
- used for skin lesions (port-wine, telangiectasias, hemangioma)
- primarily absorbed by pigmented tissues
- penetrates to the dermis
- more scatter than CO2 laser
Describe the role of flashlamp excited dye laser in skin resurfacing.
- primarily used for cutaneous lesions
- less scarring and hypopigmentation than Nd:YAG
When is treatment indicated for post-operative erythema in a pt who underwent CO2 laser resurfacing?
- erythema can last 3-6 months
- focal areas of intense erythema indicate areas predisposed to scar, may treat with strong topical corticosteroids
- Topical ascorbic acid can be applied after 10d to reduce erythema
When is treatment indicated for post-operative acne in a pt who underwent CO2 laser resurfacing?
- This is a common occurrence due to aberrant follicular reepithelialization
- First step is to remove occlusive dressings
- After at least 1 mo, can use topical erythromycin, clindamycin, tretinoin, glycolic acid, or azelaic acid compounds are beneficial
When is treatment indicated for post-operative milia in a pt who underwent CO2 laser resurfacing?
- Milia are usually superficial and resolve without specific treatment.
- tretinoin or glycolic acid preparations may be used or lesions can be manually extracted after the first postoperative month
Incidence of post-inflammatory hyperpigmentation in laser resurfacing patients?
- 33% total
- near 100% of Fitzpatric type IV or greater
- Delayed‐onset hypopigmentation is a potentially serious and permanent complication of laser resurfacing.
What are the benefits for topical vitamin C?
- increases collagen synthesis
- reduce elastin accumulation
- reduces pigment darkening
- maintains hydration by protecting the epidermal barrier
- photoprotective effects including the reduction of erythema, sunburn cell formation, and immunosuppression.
What is dermabrasion?
- Mechanical removal of the epidermis.
- Higher risk of infection than laser
- stimulates the formation of new skin.
- collagen formation will continue for 12-18 producing a youthful appearance.
- can improve scars and skin lesions
- 10-14 day healing period with intense would care
lasers of choice in nonablative laser rejuvenation
- CO2: mild-moderate rhytids in the perioral area, crow’s feet, glabellar rhytids, diffuse actinic damage and dyschromias.
- Er:YAG: similar to the CO2 except there is no coagulative necrosis and less tissue interaction
During dermabrasion, how do you know when to stop.
- When you see pinpoint bleeding, that's the papillary dermis
- the reticular dermis has parallel white collagen structures and adnexal structures that need to be avoided
- no scarring if you stay in the papillary dermis
preoperative and postoperative care in dermabrasion
- topical tretinoin for 2 weeks prior to dermabrasion
- occlusive dressing post-op
What are the benefits of collagen as an injectable filler?
- current gold standard
- 3% allergic rate
- rapidly absorbed, 6 mo
- Human: cosmoderm, cosmoplast
- Bovine: zyderm, zyplast
How are autologous fibroblasts administered as an injectable filler?
- Punch biopsy
- fibroblasts cultured 4-6 weeks
- test dose
- 3-4 injections over 6 months
What are the benefits of hyaluronic acid derivatives as an injectable filler?
- GAG polymer found in the dermis of all species
- absorbs water, expands
- lasts 6-12 months
- pain, bruising expected
- Restylane, juvederm
What are the benefits of micronized alloderm (cymetra) as an injectable filler?
- injected into subdermis
- histologic evidence of fibroblast ingrowth and collagen deposition
- longevity unclear
What are the benefits of calcium hydroxyapatite (Radiesse) as an injectable filler?
- identical to mineral component of bone
- effect is permanent after fibroblast ingrowth
- placed in deep dermis
What are the benefits of poly-L-lactic acid (PLLA, Sculptra) as an injectable filler?
- degraded and replaced by collagen
- deep dermal or supraperiosteal injection
- effect lasts 2 years
Mechanism of action of Botox?
- From clostridium botulinum toxin A (toxin B also used medically, Myobloc)
- lasts 3-4 months