2015年12月10日 星期四

Chemical peels


Mechanism of action:
l   KERYOLITIC agents
l   Due to a low pH peels are able to denature (breakdown) proteins within the skin.
l   This results in skin necrosis or death.

Methods used to increase the depth of treatment:
l   Stretching the skin, rubbing, overcoating, using wetter gauze, and employing closer intervals.

Why degrease?
l   The skin is cleansed with alcohol and acetone-soaked sponges to remove cutaneous oils. The skin is scrubbed lightly first with alcohol until the dark film or accumulation on the sponge disappears or is significantly reduced. This dark film is a good indication of the amount of oil that needs to be removed. After two cleansings with alcohol, an additional single cleansing with acetone is performed. Removal of the surface oils standardizes the condition of the skin for an even absorption of the chemical solution

Skin preparation:
l   Important in that it:
    Increases the speed of re-epithelialisation of the skin post peel
    Encourages a uniform penetration of the peeling agent
    Decreases the risk of PIHP
    Establishes patient compliance
    Introduces them to a maintenance regime
l   Some suitable key ingredients in skin preparation include:
    AHAs: Glycolic acid, Lactic acid
    Salicylic acid
    Retinoic acid

Depth
l   Very superficial: removes the stratum corneum to the stratum granulosum
l   Superficial: removes part or all of the epidermis to the basal layer
l   Medium depth: removes all of the epidermis to the papillary dermis
l   Deep: removes all the epidermis, papillary dermis to the reticular dermis

Intervals
l   v. superficial peels require 1 week between peels
l   Superficial peels require 2 weeks between each peel
l   3 to 6 sessions usually

Very Superficial to superficial peeling
Mechanism of action:
l   Involves the topical use of mild exfoliating chemicals to rejuvenate actinically damaged facial skin and to treat acne, pigmentary disturbances, fine wrinkling, and superficial scarring. On a cellular level, it produces: Thickening of the epidermis. Even removal of the stratum corneum will stimulate epidermal growth. Removal of damaged or abnormal cells in order to replace them will normal more organised cells. Induction of an inflammatory reaction deeper in the tissue than the peeled layers. Through inflammation, synthesis of new collagen and ground substance is deposited in the dermis.
Indications:
l   Rejuvenation of the Skin: Many people with fine-wrinkling, poikilodermatous changes, and simple weathering of the skin will benefit from superficial peeling.
l   Acne: Light peeling is a safe and effective adjunct in the treatment of acne vulgaris. The majority of acne patients are suitable candidates for light peeling, which affords good exfoliation. Light peeling produces a more rapid resolution in actively scarring acne and affords significant improvement in scarring.
l   Pigmentary changes: Melasma, berloque dermatitis, and postinflammatory pigmentary changes usually respond rapidly and predictably to two or three light peels at weekly intervals and twice daily use for 2 weeks of Kligman’s Formula (a hydroquinone, retinoic acid, and triamcinolone bleaching cream).
l   Moderate Wrinkling, Actinic Damage, and Scarring: Many patients with moderate wrinkling and actinic damage or shallow scarring of the skin will benefit from light peeling.
Contraindications:
l   Pregnancy/lactation
l   Recent Roaccutane therapy (< 6months)
l   Broken skin
l   Cold sores (do not apply the peel to close to the lip border or nostrils)
Types:
l   Glycolic acid: Smaller molecular weight - deeper penetration, though increase irritation.
l   Lactic acid: Found naturally in the body, thought to be more moisturising due to an extra hydroxyl group, slightly larger molecule hence reduced irritation.
l   Jessner’s
l   TCA 10% = superficial peel
Advantages:
l   Minimal risks
l   No anaesthesia required
l   Moderate to excellent improvement to pigmentation
l   Mild improvement to skin texture
Disadvantages:
l   No. of sessions required
l   Uncomfortable
l   Visible peeling
l   Possible PIHP (none with very superficial peeling)
Application:
l   Skin is cleansed and degreased using acetone or an alcohol swab
l   Peels is applied using a brush or cotton swabs
l   Left on for 2 to 5 minutes, removing “hot spots” before
l   Diluted with water and/or neutralized with water and sodium bicarbonate
After care:
l   The skin will be sensitive for 1 to 4 days
l   Bland skin care products (sorboline, cetaphil!, aqueous etc.)
l   Specific post peel skin care range (branded)
l   SPF 30+
l   Avoid direct sun exposure
l   Always provide the patient with written after care instructions
Downtime:
l   Day 1 to 3 Mild erythema for 2 to 48
l   Day 2 to 7 Mild exfoliation (not often visible)

Medium depth peels
Advantages:
l   One-off procedure
l   Excellent improvement to pigmentation and skin texture
l   Effectively treats actinic keratosis
Disadvantages:
l   Anaesthesia
l   Very noticeable peeling
l   7 - 14 days downtime
l   Risk of PIHP
l   Risk of infection

Deep peels
Advantages:
l   One-off
l   Excellent results in treating pigmentation, severe sun damage and skin texture
Disadvantagaes:
l   The deeper peels are more painful and expensive. It is also more risky.
l   Anaesthesia
l   Extreme peeling
l   14 to 21 days downtime
l   Risk of PIHP and permanent hypopigmentation
l   Risk of infection
Frosting
l   The visible denaturing of the skin
l   The deeper the peel - the more frosting
l   Cannot be washed off (different to the salicylic precipitate)
l   Lasts 10 to 30 minutes after the peel
l   Indicates the amount of exfoliation the patient will have

AHA:
l   The product used at laser clinic: 20% glycolic/lactic acid peel. The glycolic acid penetrates deeper while the lactic acid is more moisturizing.
l   Indications: someone who’s first starting out with skin treatment
l   Procedure:
n   After washing & drying face, prepare a big bowel of water and a small bowl of water which should have a scoop of sodium bicarb for neutralizing acid.
n   Pour the AHA just to fill the bottom of the tiny glass bowl. 
n   Dip brush into the acid and make sure it’s not dripping wet.
n   Press timer as soon as starting and paint left to right: forehead, R. face & chin (remember to really sweep to the sides), L. chin & face, then nose & above upper lip within 30 seconds.
n   Leave on for 3-4 minutes. “Pitter patter” (like playing piano) on skin whilst waiting.
n   At 30 seconds before the intended off time, use face wipe in water to rinse x3 the AHA but just dab (not rubbing motion because that can make it more painful).
n   Then at the intended off time, neutralize with sodium bicarb x3, and ask client if there are any areas still tingling and neutralize more on those areas.
n   Dry face.
n   Put on aftercare products in a pat on and push motion.


Jessner:
l   14% Salicylic acid, 14% Resorcinol, 14% Lactic acid
l   Indications: Good for oily skin.
l   Contraindications specific for Jessner: Heart condition, allergy to aspirin.
l   Advantages of Jessner’s over TCA are that there is no danger of using the wrong concentration of solutions, no need to neutralize the solution, and therefore no need to time the duration of applications.
l   However, salicylic Acid is toxic in large doses, resulting in salicylism (headaches, nausea and tinnitus). Resorcinol is cardio toxic in large doses. On small areas such as the face and neck is fine, whereas toxicity can occur when applied to a large percentage of the body ie. back, legs and arms.
l   Procedure:
n   Use petroleum jelly to areas that you do not wish to peel using cotton bud: on lips, inner corner of each eye over the lower eyelids, and any cuts/open wounds/dermatitis.
n   Applied with brushes or gauze squares. Gauze cut in half and folded into a small pillow, 1/3 then another 1/3 the other direction, is the better option as it has a lower risk of infection than reusable brushes.
n   Dip gauze in acid. Handle with right hand only. Squeeze out any excess dripping liquid. Wipe off any excess liquid on R. hand with tissue. 
n   Applied with meticulous strokes in order not to overlap, starting from forehead and working downwards. Pressure should be firm and a slow drag across skin.
n   Client is given a fan for comfort.
n   Your goal is to create an even peel.
n   Normally 1 to 5 layers can be applied. This will depend on the skin reaction after each layer. Discomfort peaks at 4 minutes so ask how client is feeling at this point before applying a second layer.
n   With each layer more frosting is achieved.
n   Does not need to be neutralized
n   Don’t wash face for 6 hours after the application.
n   Aftercare products: just put sunscreen, don’t put the Vitamin B or redless.

TCA:
l   Indications: Best effects for moderate to severely sun damaged skin.
l   TCA is not good for the darker skin types because of the risk of PIHP when the skin is peeled too deeply.
l   Procedure:
n   Same as Jessner.
n   Normally 1 to 3 layers can be applied
n   Aftercare products: just put sunscreen, don’t put the Vitamin B or redless.


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