(A) actinic skin damage and fine wrinkle formation
(B) the potential for pigmentary changes following chemical peeling
(C) their risk for cardiac toxicity associated with phenol peeling
(D) their risk for hypertrophic scarring following skin resurfacing
(E) thickness and laxity of facial skin

The correct response is Option B.

Fitzpatrick's system is the most widely used method for classifying patients according to skin type in order to stratify their risk for the development of postinflammatory hyperpigmentation following chemical peeling and laser skin resurfacing. This method of classification is based on the patient's skin pigmentation and subsequent response following exposure to ultraviolet light. A table representing this classification system is shown below.

Patients who have Fitzpatrick type I, type II, or type III skin have the lowest risk for development of hyperpigmentation following chemical peeling. In contrast, patients with type IV, type V, or type VI skin are at increased risk for pigmentary changes.

References
1. Rubin MG, ed. Manual of Chemical Peels; Superficial and Medium Depth. Philadelphia, Pa: JB Lippincott Co; 1995:3.
2. Stuzin JM. Phenol peeling and the history of phenol peeling. Clin Plast Surg. 1998;25:1-19.

A 42-year-old woman who desires correction of perioral and periorbital rhytids begins therapy with 0.025% tretinoin. Which of the following responses is most likely to be seen in this patient?

(A) Hypertrichosis
(B) Increased type III collagen
(C) Partial-thickness burn
(D) Subcutaneous atrophy
(E) Thinning of the dermis

The correct response is Option B.

Histologically, long-term application of tretinoin results in the formation of new type III embryonic collagen; this process is believed to be caused by activation of fibroblasts. This derivative of vitamin A, also known as retinoic acid, results in obliteration of atypia and microscopic actinic keratoses when applied once daily at a strength of 0.025% to 0.05%. Improvement of rhytids is not immediate, occurring instead over six to 12 months. During this time, the dermis becomes markedly thickened and the elasticity of the skin greatly increases; the latter is due to an increase in collagen levels of as much as 80%. Adverse effects are frequent and may include erythema, peeling, xerosis, pruritus, and the onset of a sunburn sensation.
Use of retinoic acid does not affect hair growth or loss. A partial-thickness burn is never associated with tretinoin therapy.

References
1. Cohen M, ed. Mastery of Plastic and Reconstructive Surgery. Boston, Mass: Little, Brown & Co; 1994;3:1997.
2. Kligman AM, Grove GL, Hirose R, et al. Topical tretinoin for photoaged skin. J Am Acad Dermatol. 1986;15:836.

PHOTO

The above photograph is of a 56-year-old man who has pitted acne scars and ruddiness and oiliness of the skin surface. He desires improvement in the appearance of his skin. Which of the following is the most appropriate management?

(A) Alexandrite laser therapy
(B) Injection of bovine collagen
(C) Dermabrasion
(D) Oxygen therapy
(E) Punch excision

The correct response is Option C.

The most appropriate management of this patient's acne scars is dermabrasion. This skin resurfacing technique, which can be used to improve acne scarring, is performed with a motorized instrument and diamond fraises. The appropriate depth of the dermabrasion is indicated by the onset of punctate bleeding; any deeper dermabrasion can result in hypertrophic scarring. However, even after treatment the scars may be perceptible, and patients who have deep "ice pick" acne scars, which are especially recalcitrant to treatment, may need to undergo multiple sessions or subsequent surgical excision.

Carbon dioxide laser resurfacing is an alternative to dermabrasion that can be used to improve either acne scarring,
Alexandrite lasers are used to remove hair or tattoos. Although bovine collagen can be injected to temporarily fill small acne scars, its effects generally last for only three to six months. In addition, as many as 3% of patients can experience a delayed hypersensitivity reaction. Oxygen therapy is a modality often used in spa-like settings. It cannot be used to improve acne scarring. Because punch excision is limited to small areas, it would not be effective for resurfacing this patient's widespread acne scars.

References
1. Chiu DT, Edgerton BW. Repair and grafting of dermis, fat, and fascia. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;1:519-520.
2. Roenigk HH Jr. Dermabrasion: state of the art. J Dermatol Surg Oncol. 1985;11:306.

Which of the following topical agents provides effective protection against long-wave ultraviolet A, short-wave ultraviolet A, and ultraviolet B radiation?

(A) Octyl dimethyl paba (PABA)
(B) Octyl salicylate (OCS)
(C) Oxybenzone (Benzophenone-3)
(D) Titanium dioxide
(E) Zinc oxide

Reproduced with permission of Pinnell SR, Maday DL. New and improved daily photoprotection: microfine zinc oxide (Z-Cote¨). Aesthet Surg J. 1999;19:260-263.

The correct response is Option E.

Zinc oxide is the only agent that has been shown to be effective against all ultraviolet A and ultraviolet B rays. While ultraviolet A rays are believed to contribute to elastic tissue damage and skin aging because of their constancy, ultraviolet B rays are thought to be the primary cause of most sunburns and acute skin damage due to their intensity during summer months. It is important to note that the SPF rating of a sunscreen measures its effectiveness against ultraviolet B radiation only. Because the overall effect of solar exposure on skin aging should instead be measured primarily by long-term exposure to both ultraviolet A and ultraviolet B radiation, it is important to use a sunscreen
Octyl dimethyl paba (PABA), octyl salicylate (OCS), and octyl methoxycinnamate (OMC) provide effective protection against ultraviolet B rays only. In contrast, oxybenzone (Benzophenone-3) protects against skin damage from short-wave ultraviolet A radiation. Titanium dioxide is effective against short-wave ultraviolet A as well as ultraviolet B radiation.

References
1. Green HA, Drake L. Aging, sun damage and sunscreens. Clin Plast Surg. 1993;20:1-8.
2. Mitchnick MA, Fairhust D, Pinnell SR. Microfine zinc oxide (Z-cote) as a photostable UVA/UVB sunblock agent. J Am Acad Dermatol. 1999;40:85-90.
3. Pinnell SR, Maday DL. New and improved daily photoprotection: microfine zinc oxide (Z-Cote¨). Aesthet Surg J. 1999;19:260-263.

In a 47-year-old woman who has used topical tretinoin for the last four years, which of the following histologic features is most likely?

(A) A compact stratum corneum
(B) A decrease in dermal mucin
(C) A decrease in epidermal thickness
(D) A decrease in hyaluronic acid
(E) An increase in melanin production

The correct response is Option A.

Topical tretinoin (Retin-A) can be used to decrease the effects of photoaging, including those resulting from solar exposure. Long-term studies have uncovered several histologic features resulting from the topical application of tretinoin, including compactness of the stratum corneum, which produces smoothing of the skin; an increase in hyaluronic acid, which is thought to reduce the appearance of fine lines; an increase in epidermal thickness with return of the granular layer thickness to a baseline value; an increase in dermal mucin; and a decrease in melanin production.

Adverse effects associated with tretinoin use include erythema and crusting of the skin. Alternate-day therapy or daily therapy using a dilute dose has been shown to decrease these effects. Because tretinoin is also associated with sun sensitivity, skin protection during sun exposure is advocated.

References
1. Green HA, Drake L. Aging, sundamage and sunscreens. Clin Plast Surg. 1993;20:1-8.
2. Leyden JJ. Treatment of photodamaged skin with topical tretinoin: an update. Plast Reconstr Surg. 1998;102:1667-1671.
3. Rubin MG. Trichloroacetic acid and other non phenol peels. Clin Plast Surg. 1992;19:525-536.