A patient requests bovine collagen injection for correction of glabellar frown lines. Following administration of the required test dose, this patient should be observed for potential development of adverse effects for how long?

(A) 1 hour
(B) 1 day
(C) 1 week
(D) 1 month
(E) 1 year

The correct response is Option D.

Following injection of a test dose of bovine collagen (Zyderm/Zyplast), the patient should be observed for one month in order to note the development of any adverse effects. Clinical studies have reported hypersensitivity reactions in 3% of otherwise healthy persons who undergo skin testing. A hypersensitivity reaction is defined as the onset of erythema, induration, or swelling at the test site. Approximately 70% of these reactions occur within 72 hours, 10% occur within one week, and the remaining 20% occur within four weeks. If the patient has no signs of hypersensitivity at that time, the bovine collagen can then be injected into the glabellar frown lines.

It should be noted that 1% to 4% of patients who have nonreactive skin tests subsequently develop hypersensitivity reactions following treatment with injectable bovine collagen.

References
1. Moscona RR, Bergman R, Friedman-Birnbaum R. An unusual late reaction to Zyderm I injections: a challenge for treatment. Plast Reconstr Surg. 1993;92:331-334.
2. Spira M, Rosen T. Injectable soft tissue substitutes. Clin Plast Surg. 1993;20:181-188.

A 39-year-old woman desires correction of deep frown lines between the eyebrows and at the bridge of the nose. Five injections of botulinum toxin (2.5 units per injection) are administered. Three days later, the patient says that she has not experienced improvement of the frown lines.

Which of the following is the most likely cause of the current findings?

(A) Excessively superficial level of injection
(B) Inactive toxin
(C) Inadequate dose of botulinum toxin
(D) Inadequate time for onset of action
(E) Prior immunity to botulinum toxin

The correct response is Option D.

Although botulinum toxin, an exotoxin of Clostridium botulinum bacteria, is currently only approved by the FDA for use in patients with strabismus and blepharospasm, it is increasingly being used for temporary eradication of facial wrinkling. Its neuromuscular mechanism of action occurs by preventing acetylcholine uptake. It must be reconstituted just prior to use, refrigerated, and then used within 48 hours (before the potency diminishes). Small doses (2.5 U) per site are injected directly into the muscle belly, with paralysis occurring within three to seven days and lasting for four to six months.

Because this patient has only waited three days since injection, the most likely explanation for the absence of paralysis at the treatment site is that the time for onset of action has been inadequate.

Complications resulting from botulinum toxin use are typically related to inadvertent diffusion of the toxin to the surrounding musculature. Potential diffusion can be minimized by using highly concentrated doses of the toxin, localizing the injection to the involved muscle, and instructing the patient to avoid any bending or straining following injection. Systemic and immunologic side effects may also be seen but are uncommon.

References
1. Fagien S. Botox for the treatment of dynamic and hyperkinetic facial lines and furrows: adjunctive use in facial aesthetic surgery. Plast Reconstr Surg. 1999;103:701-713.
2. Matarasso A, Matarasso SL, Brandt FS, et al. Botulinum A exotoxin for the management of platysma bands. Plast Reconstr Surg. 1999;103:645-652.
3. Matarasso SL. Complications of botulinum A exotoxin for hyperfunctional lines. Dermatol Surg. 1998;24:1249-1254.

Which of the following best describes the mechanism of action of retinoids on the skin?

(A) Decreased activation of metalloproteases resulting from inhibition of AP1 transcription
(B) Decreased free radical-mediated damage to the skin
(C) Increased desquamation resulting from diminished corneocyte cohesion
(D) Increased gene transcription of collagen types I and III
(E) Inhibition of the conversion of dopamine to melanin

The correct response is Option A.

The mechanism of action of retinoids involves decreased activation of metalloproteases through inhibition of AP1 transcription. Retinoic acid has been shown to reverse the effects of photoaging, while use of tretinoin results in thinning of the stratum corneum, thickening of the epidermis, reversal of atypia, and increasing collagen synthesis within the dermis, with angiogenesis and a more even dispersion of melanin granules. One report that studied the continuous use of retinoids for longer than four years showed improvement of rhytids and hyperpigmentation and increased skin smoothness. The mechanism of action of retinoids has been shown to occur through binding to a DNA receptor. The activated receptor then inhibits AP1 transcription factor, which inhibits the activation of such metalloproteases as collagen, gelatinase, and stromelysin.

Topical vitamin C is an experimental agent that has demonstrated promising results in limited studies. It has been shown to decrease the free radical-mediated effects of UVB radiation in mouse models, as well as to stimulate cultured fibroblasts, resulting in increased production of collagen types I and III through an increase in gene transcription. The mechanism of action of alpha-hydroxy acids, which gradually reduce fine rhytids, is thought to occur through increased desquamation resulting from diminished corneocyte cohesion immediately above the granular layer in the epithelium. Hydroquinones are commonly used bleaching agents that block the conversion of dopamine to melanin through inhibition of the tyrosinase enzyme.

References
1. Clark CP III. Office-based skin care and superficial peels: the scientific rationale. Plast Reconstr Surg. 1999;104:854.
2. Leyden JJ. Treatment of photodamaged skin with topical tretinoin: an update. Plast Reconstr Surg. 1998;102:1667.

Dermabrasion is most appropriate for the treatment of which of the following conditions?

(A) Actinic keratoses on the cheeks
(B) Decorative tattoo on the upper back
(C) Hypertrophic burn scar of the shoulder
(D) Ice-pick acne scars
(E) Traumatic tattoo of the chin

The correct response is Option E.

Dermabrasion, which is a method of skin resurfacing involving abrasion of the epidermis, is especially useful for treatment of perioral rhytids and traumatic tattoos. Because traumatic tattooing involves the embedding of particulate matter within the superficial epidermis, dermabrasion can be used to uproot and remove the debris. Unlike chemical peeling and laser resurfacing, dermabrasion is an imprecise technique that can result in the development of complications if the abrasion is performed at a level deeper than the upper third of the dermis. These complications, which include hypertrophic scarring, hypopigmentation, and an enhanced, porous look to the skin, are more common in areas more distal to the head and neck because these regions have a decreased density of adnexal structures, which lie within the dermis and supply basal keratinocytes for skin resurfacing.

Options for treatment of sun-induced actinic damage of the cheeks include laser resurfacing, trichloroacetic acid peeling, and topical application of 5-fluorouracil. The use of dermabrasion for the removal of decorative tattoos is associated with a high incidence of postoperative scarring; again, a laser is the choice for removal. Dermabrasion will not effectively remove hypertrophic scars or keloids. Excision is preferred for management of ice-pick acne scars.

References
1. Baker TM. Dermabrasion: as a complement to aesthetic surgery. Clin Plast Surg. 1998;25:81-88.
2. Orentreich N, Orentreich DS. Dermabrasion: as a complement to dermatology. Clin Plast Surg. 1998;25:63-80.