• Fitzpatrick skin type system

The Fitzpatrick skin type system classifies degrees of pigmentation and ability to tan using grades I to VI. It prognosticates sun sensitivity, susceptibility to photodamage and ability for facultative melanogenesis (one’s intrinsic ability to tan). In addition, this system classifies skin as to its risk factors for complications during chemical peeling or other resurfacing procedures. Fitzpatrick skin types take into account both color and reaction to the sun. Skin types I and II are pale white and freckled with a high degree of potential to burn with sun exposure. Types III and IV can burn but usually are an olive to brown coloration. Types V and VI are dark brown to black skin that rarely ever burn and usually do not need sunscreen protection (Table 14.2).

Table 14.2 Fitzpatrick’s classification of skin types

The patient with type I or II skin with significant photodamage needs regular sunscreen protection prior to and after the procedure. The patient, though, has little risk for hypopigmentation, reactive hyperpigmentation or postinflammatory hypopigmentation (PIH) after a chemical peeling procedure. However, a patient with any of the skin types from III to VI has a greater risk for pigmentary dyschromia – hyper or hypopigmentation – after a chemical peel and may need pre and post treatment with both sunscreen and bleaching products to prevent these complications. Pigmentary risks are generally not a great problem with very superficial and superficial chemical peeling but may become a significant problem with medium and deep chemical peels as well as CO₂ or fractional laser resurfacing. It can also be a risk when regional areas such as lips and eyelids are peeled with deep peeling or pulsed CO₂ laser, creating a significant color change in these cosmetic units from the rest of the face. This has been classified as the ‘alabaster look’ that is seen with taped, deep chemical peels in regional areas. This is an objectionable side-effect of deep taped phenol peeling, and to a lesser extent with laser resurfacing, and should be avoided now as patients demand a natural look. Though this was an acceptable look in the 1970s, it is generally not tolerated in the new millennium. The physician must inform patients of this potential problem (especially those with skin types III to VI) for full face deep peels or resurfacing procedures, justifying the benefits of the procedure, outweighing these risks and, in addition, plan for the appropriate techniques to prevent these unwanted changes in color.

• Glogau system

The Glogau system classifies severity of photodamage, taking into account the degree of epidermal and dermal degenerative effects. The categorization is from I to IV, ranging from mild, through moderate and advanced, to severe photodamaged skin. These categories are devised for therapeutic intervention. Type I in young individuals or minimal degree photodamage should be treated with light chemical peeling and medical treatment. Types II and III would entail medium-depth chemical peeling, while type IV would need those modalities listed plus cosmetic surgical intervention for gravitational changes (Box 14.2). Type III or IV can have combination procedures dependent on the degree of damage in each area.

Based on Glogau RG 1994 Chemical peeling and aging skin. Journal of Geriatric Dermatology 2(1):30–35

• Index of photoaging skin

The index of photoaging skin is a system of quantitating photodamage and using numerical scores that would fit into corresponding rejuvenation programs. In analyzing photodamage, the major categories include epidermal color, skin lesions, textural changes, and dermal changes. Photoaging changes include wrinkles, cross-hatched lines, sallow color, leathery appearance, crinkly thin parchment skin, and the pebblish white nodules of milia. Each of these is classified, giving the patient a point score of between one and four. In addition, the number and extent of lesions are categorized from freckles, lentigines, telangiectasias, actinic and seborrheic keratoses, skin cancers, and senile comedones. These are also added in the classification system and the final score results are tabulated. A total score of between one and four indicates very mild damage and the patient would adequately respond to a five-step skin care program including sunscreen protection, retinoic acid, glycolic acid peels and selective lesional removal. A patient scoring between five and nine requires all of the above, plus a repetitive superficial peeling agents program such as glycolic acid, Jessner’s solution or lactic acid peels. A score of 10–14 suggests the inclusion of medium-depth chemical peeling, and if a patient scores 15 or above the practitioner will be including deep peeling or laser resurfacing in the treatment (Figs 14.1 and 14.2). Thus, the patient can understand during the consultation the degree of photodamage and the necessity for an individual peeling program (Table 14.3). The system can also quantitate individual cosmetic units indicating more aggressive resurfacing for the lids and/or lips than surrounding cheeks and forehead.

Figure 14.1 The index of photoaging skin can separate severity of damage and guide the appropriate combination of procedures. Moderate damage is shown in these photographs

Figure 14.2 Severe damage, as determined by using the index of photoaging skin

The chief indications for chemical peeling are associated with the reversal of actinic changes such as photodamage, rhytids, actinic growths, pigmentary dyschromias, and acne scars. The physician thus can use his classification systems to quantitate the level of photodamage and prescribe the appropriate chemical peeling combination.

• Superifical chemical peeling

Minimally aggressive procedures are commonly combined with superficial chemical peels to enhance the benefits of these procedures. Light chemical peels commonly used include:

Each of these agents has its own characteristics and methodology and a physician must be thoroughly familiar with the chemicals, methods of application, and the nature of healing. The usual time for healing is from 1 to 4 days depending on the chemical and its strength. These agents range from noninflammatory (salicylic acid peels) to moderately inflammatory (Jessner’s solution) and each has a specific purpose (Fig. 14.3).

Figure 14.3 Spectrum of superficial chemical peeling

Cosmeceutical pharmaceutical agents are commonly combined with chemical peels to enhance exfoliative and regenerative effects. Retinoic acid preparations are prescribed as daily home care to accelerate epidermal proliferation, so there is an increase in epidermal thickness despite the stratum corneum being shed. The application of retinoic acid enhances the effectiveness of light and even medium-depth chemical peeling to texture, tone, and smooth the skin. Used in combination with alpha-hydroxy acids (AHAs) retinoic acid prepares the skin for the peel procedure.

Glycolic acid creams, cleansers, and exfoliating preparations are used to boost epidermal exfoliation, reduce stratum corneum thickness and augment the peel penetration, thus enhancing the uniformity of the light chemical peel. Pretreatment is also essential for combination medium-depth peels.

Sunscreens are necessary accompaniments to all peeling procedures and the patient should begin this prior to the peel. The proper FDA approved sunscreen should be chosen based on the patient’s skin type and procedure chosen. The choices are UVA filters, UVB filters and inorganic sunscreens (Table 14.4).

Table 14.4 Sunscreens and their photo protection

When treating pigmentary problems such as melasma, reactive pigmentary dyschromias or treating skin types III–V, the peeling procedure should be accompanied by a topical bleaching product, retinoic acid and a sunscreen. Hydroquinone is a pharmacologic agent that blocks the enzyme tyrosinase from developing melanin precursors for the production of new pigment. Its use will block the production of new pigment as the new epidermis is healing after a chemical peel. Together, this topical combination of hydroquinone, retinoids and sunscreens will enhance the effect of the peel for pigmentary problems. Pretreatment should be instituted six weeks prior to the peel procedure for maximal benefit.

The peeling agent of choice to use for light pigmentary problems