INTRO TO CHEMICAL PEELING

In technical terms, the word peeling means shedding or scaling, including exfoliation.  In other words, generating by one or various mechanisms the controlled and rational loss of one or more layers of the skin.  This effect can be caused chemically by using substances in solutions, mechanically by using for example diamond crystals, silica or aluminum hydroxide (microdermabrasion), or caloric with the use of ablative lasers.
In dermo-cosmetics, this technique produces an accelerated cell renovation of the skin layers with diverse objectives like cleansing, nourishing, moisturizing, astringency, de-pigmentation remodelling effects, etc.

Immediate epidermal effects:

- Reduction of cohesion of corneocytes in the lower stratum corneum, facilitating their elimination.
- Union between the stratum corneum and stratum granulosum.
- Fewer filaments in the cytoplasm of basal cells.
- More uniform dispersion of melanin, regulates the melanocyte population and eliminates the extra cellular pigmentation.
-  Skin is more consistent to the touch, smoother, and pinker. 

Delayed dermal effects:

- Increase the thickness of the epidermis and papillary dermis with proliferation of fibroblasts (collagen and elastin synthesis).
- Increase of glycosaminoglycans (hyaluronic and basic intracellular sustenance)
- Increased production of collagen, with more fibers which are better organized.
- Improved quality of elastin fibers; longer and less fragmented.
- Evident reduction of wrinkles and non fibrous scars.

The results are better hydrated, soft and smooth skin, reduction in the depth of wrinkles and scars, and an attenuation or elimination of pigment spots. Improvement can be made in pathologies depending on the selected active ingredients.

Chemical peeling is a good, hardly evasive option, which helps maintain healthy, cosmetically beautiful skin which inhibits and even reverses the effects of aging, helping to improve existing conditions and can be combined with other procedures such as microdermabrasion, mesotherapy, laser and IPL's, botulinum toxin and dermal fillers.

Chemical peels can make a difference at different depths in the skin, and accordingly, are divided as follows:

a)      Very superficial (only the stratum corneum).
b) Surface (to the basal layer).
c) Medium and its variants (papillary dermis).
d) Deep and its variants (reticular dermis).

The depth depends on several factors including the type of chemical used, the concentration of this chemical, skin type, time in contact with the skin (gel based peels), the number of layers applied to the skin (solution based peels), the application technique and how the skin was prepared before the peeling. (pre-peeling phase.)

This classification helps to choose the chemical in accordance with the depth of the lesion to be treated, taking into account that this is not absolute and emphasizing that any chemical agent, depending on the various factors mentioned above, can change its action and behave as a superficial / medium or  medium / deep peeling.

Very superficial (stratum corneum)

• 30% Salicylic Acid - One or more layers.
• glycolic acid - 1 to 2 layers, less than 5 minutes.
• Melaspeel - 1 to 2 layers
• Resorcinol - 1 to 2 layers
• Trichloroacetic acid (TCA or ATA) 10% to 25% - One layer

Superficial (epidermal)

• glycolic acid - 2-4 layers, for 5 to 10 minutes.
• Thioglycolic acid - more than 2 layers.
. Mandelic acid - 2-4 layers, for 2 to 20 minutes
• Melaspeel, improved Jessner's solution - 2-4 layers
• Resorcinol - 2-4 layers
• Trichloroacetic acid (TCA) 10% to 30%.

Medium (papillary dermis)

• Trichloroacetic acid (TCA) 35% to 50%, 4-6 layers
• Glycolic acid - for more than 10 minutes
• Mandelic acid 50% - from 5 to 30 minutes
• Melaspeel (Jessner) - more than 4 layers

• Melaspeel + TCA 35%
• Glycolic Acid + TCA 35%

• Pyruvic acid
• Melaspeel + glycolic acid 40% to 70%

Deep (reticular dermis)

• Phenol (not available in USA).

Comparison between the type of lesion and class of peel you choose
Based on the depth needed and according to the histological events of each pathology, making clear that epidermal skin lesions, only need focal treatment, while lesions that need the dermis modified, especially photo-aging should work in the first as well as the second skin layer.

Actinic keratosis - Medium / deep  

Wrinkles: light – Superficial / medium; Moderate – medium; Severe – Medum / deep 
Hyperpigmentations
Superficial Melasma – Superficial
Mixed Melasma – Medium / deep
Post inflammatory hyperpigmentations – superficial / medium / deep 
Scars – Medium
Acne
Active – Superficial
Regressive – Medium
Marks – Superficial / medium 
Rosacea – Superficial / medium 
Seborrheic Dermatitis – Superficial 

Factors which affect the depth of peels.
The depth achieved depends on many variables, including:
- Concentration of the active ingredient used.
- In gel peels, depth depends on contact time.
- In solution peels, depth depends on how many layers are applied
- The application technique; massaging will increase the depth.
- The frequency of application.
- Integrity of the epidermis.
- Proper cleaning and degreasing of the skin before treatment
- Skin preparation in the weeks leading up to the peeling
- Thickness of the skin
- The type of skin (thin or thick, tenderness, presence of a skin disease ...)
- The anatomical location of the area to exfoliate (face or non-facial area)

ACTION MECHANISM

Chemical peeling causes alterations in the skin by three mechanisms.  

• Stimulation of epidermal growth through removal of the stratum corneum, dermal thickening by mild peeling at the papillary dermis level.
• Destruction of specific layers of damaged skin, depending on the depth of the lesion.
• Activation of inflammatory mediators, which induces the production of new collagen and fundamental dermal substance. 

In the case of injury, after the initial epidermal injury caused by the application of the chemical agent, there is an initial migration of keratinocytes in the edges of the wound and the epithelium of the annexes at the base of the lesion. Later, cell proliferation from the edges of the wound increase with the objective of forming new cells to cover the injury. From an anatomical point of view, the skin of the face is different from the regions of the body because of the relatively large number of pilosebaceous units, resulting in a faster re-epithelialization. The nose and forehead have more sebaceous glands than the cheeks.  Due to this, facial scarring always increases as you move from the center of the face to the periphery. 

CONSIDERATIONS BEFORE THE PEELING
Based on the indications for chemical peels, all patients should be examined to determine which of the peeling agents produce the desired result with the least amount of aggressiveness, according to the patient's lifestyle, the depth of the lesions to be corrected and general characteristics of the skin to be treated.
An important consideration to prevent damage is to evaluate the skin photo type of the patient.  To do this we will use the Fitzpatrick classification.
This information is very useful in determining which patients will respond well to a chemical peeling and which will be more easily irritated by the chemical peel, or run a high risk of pigmentation (dyschromia) after the procedure. Skin types I to III are ideal for all peeling types where types IV to VI have a greater risk of developing dyschromia.

PHOTOTYPE	HAIR COLOR	SKIN COLOR	BURN	TAN
0	White	White	Always	Never
I	Red	Milky	Always	Never
II	Blonde	Clear	Often	Very light
III	Brown	Clear	Often	Light
IV	Dark brown	Dark	Rarely
V	Dark brown	Dark	Very rarely	Dark
VI	Black	Black	Never	Very dark

The prior ingestion of oral retinoids should be taken into account, since they may lead to poor healing especially in medium and deep peels.  They also boost of the effects of different peeling agents to reduce epidermal thickness and keratinocyte cohesion.

Smoking history, intake or use of photosensitizing drugs and pigmentation boosters, and previous or recent herpes outbreaks are of vital importance to prevent poor or delayed healing, pigmentation and extensive viral rashes respectively.
In case of recurrent herpes, Acyclovir is recommended 1 week before the peeling, do not peel active herpes.

IMPORTANT ASPECTS OF CHEMICAL PEELING

1. Concentration of the active ingredients

The higher concentration, the greater potential, greater effectiveness and greater irritability.

2.  pH of the peeling

As the pH increases, this indicates there is a higher concentration of ingredients in the form of salt compared to acid (active ingredient).
Important to assess the concentration of free acid and have criteria to select a suitable peeling.

If pH = pKa the formula contains a 50% of free acid and 50% of salt.

If pH>pKa in the formula, salt predominates, less potential

If pH < pka acid="" formula,="" greater="" in="" potential

3. Texture of the peeling           
GEL
- Depth of the peeling related to the contact time.
- Contact time: 5-10 minutes. (Depending of the active ingredient and the precautions described above.)
- Clean in order to neutralize.
- Slow penetration: less irritation.          

SOLUTION

- Depth of the peeling related to the quantity of the solution applied → apply by layers.
- Wait 3 minutes between each layer
Massaging (gel) or pressure applied (solution) can enhance the penetration of the peeling.

PHASES

The therapeutic success of a chemical peel, not only has to do with an appropriate choice for the patient of the exfoliating agent and proper application technique, but also compliance with the following three stages (b, c, d) which are:
a) PRE-PEELING.
b) PEELING.
c) POST-PEELING.
d) RE-PEELING

PRE-PEELING

Prepare the skin 4 weeks before the peeling using topical substances that thin the stratum corneum (retinoic acid, alpha hydroxy acids), the use of sunscreens and skin lightening agents reducing the risk of post-inflammatory hyper pigmentation.
Avoid using corticosteroids because they interfere in the inflammatory process, which is important for reepithelialization, if possible also avoid the use of estrogens and oral contraceptives, which increase the risk of post-inflammatory pigmentation, or otherwise initiate the use of previous depigmenting agents.

Provide the patient with information and instructions about the type of peel to be performed to better understand and clarify the procedures and doubts, so the patient knows exactly what to expect.
Signing an informed consent is recommended.

PEELING

Clinical documentation performed with:
Control photos (front and sides). Patients usually forget their appearance before the procedure and habitually point a pre-existing “defect”  from before the peeling.
List of important stages that should be checked during the course of the peeling.

Signing of informed consent and adequate clarification.
Instructions, in writing, to be followed in the post-peel (avoid sun and direct heat sources during the first week, constant use of sunscreen and antioxidants during the day.)

List of necessary materials to perform peelings

• Small container for mixing (if required).
• Appropriate Cleansing (makeup remover) & tonic
• Degreasing solution
• Silkses (silicone) to protect mucous membranes or sensitive areas (lips, nostrils).
• Sensyses solution (calming solution)
• non-sterile gloves.
• Gauze.
• Q-tips.
• Container with water.
• Skin Cleaning solution.
• Fan.
• Camera.
• Post-peel cream (Hidraloe facial cream or Silkses)
•  Soothing masks.

Peeling precautions
- Be careful with the patient's eyes to avoid contact with product.
- Keep the head slightly elevated by an average of 45 °.
- Have on hand a bottle on hand with clean water or saline to wash the eyes, in case of accident.
- Before you apply the exfoliating agent, ask if:

There was recent facial hair removal.
There was recent surgery on the face or neck.
There is the use of systematic tretinoin or topical isotretinoin in recent months.
A rejuvenating treatment was performed ​​recently .. (Microdermabrasion, IPL, fractional laser...).

If any of these questions are positive, the reaction may be more intense to the peeling.

- Any patient submitting to a medium or deep peeling with a history of herpes simplex should be subjected to a specific therapy a week before the procedure.
- The stinging or burning sensation associated with chemical peels is short, not constant and increases during the procedure. It is important to warn patients in advance what they will be feeling and reassure them that will be for a short time and is normal during the treatment.
- Post-inflammatory hyper pigmentation is a condition in which an inflammatory response of the skin leads to the development of hyper pigmentation. Usually it is associated with dark-skinned patients and sun exposure after the peel. The treatment of this condition can be simply waiting a time because it tends to disappear gradually over time.  Another alternative is to start a therapy with bleaching and photo protective agents. The pigmentation may occur in the post peeling stage (four to five days) or as late as two months after the peeling.
- Never do chemical peels if pregnant or nursing.
- During the first week after the peel, avoid saunas, Turkish baths and vigorous exercise.
- With men, do not shave the day of peeling.
- Wait 30 days after surgery in the treatment area before performing a peeling.
- Scrapes, facial injuries, wait 1 week before applying the peel.
- Abrasive agents, wait 1 week.

POST PEELING

Special care, especially comprehensive hydration for the week following the peeling, stop the use of aggressive creams for 3 days and have the patient become accustomed to combining  a morning antioxidant and photo protection.
Afterwards, depending on the treatment and the condition to be resolved, recommend an appropriate home treatment.

RE-PEELING

After having immediately seen the epidermal effects, the results can be intensified by the clinical use of complementary products.
The repetition of 6-12 continuous sessions, depending to pathology and maintenance sessions guarantees the effectiveness of treatment.

More information about our chemical peels is available at www.mediderm.com, or by calling 800796-0996.