Darker skin types

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21 Darker skin types

Pearl E. Grimes, Andrew F. Alexis

Summary and Key Features

• Botulinum toxin is a safe and effective procedure in darker skin types

• In general, efficacy and safety profiles are similar to lighter skin types

• With appropriate use, side effects are uncommon

• Injection techniques are similar to lighter skin types

• Commonly treated areas are glabellar and horizontal forehead lines

Introduction

Demographic trends coupled with the increased availability of minimally invasive treatment options have led to an increasingly diverse patient population in the aesthetic arena. According to the American Society for Aesthetic Plastic Surgery, 19% of the 10 million cosmetic procedures performed in the United States (US) in 2010, were performed on racial / ethnic minorities (8% Hispanic, 6% African-American, 4% Asian descent, 1% other non-Caucasian race / ethnicity). This proportion is expected to increase over the next decade as non-white racial and ethnic groups form a rapidly growing segment of the US population. Similar trends are likely to be seen globally. As such, understanding racial or ethnic variations in safety, efficacy, and approaches to treatment is of increasing importance to the aesthetic physician.

Racial / ethnic differences in photoaging

Facial rhytides are a common concern across the racial and ethnic spectrum. However, variations in severity, age of onset, and cultural impact can be seen in different populations. In general, as the studies by Hexsel & Brunetto and Rossi & Alexis reported, individuals with richly pigmented skin (i.e. Fitzpatrick skin types IV–VI) demonstrate signs of photoaging, including rhytides, at a later age than do individuals with fair skin (Fitzpatrick skin types I–III). This is largely due to the photoprotective effect of increased epidermal melanin, which has been demonstrated in several studies. Most notably, the mean protective factor from ultraviolet (UV) B in black skin was found to be 13.4 versus 3.4 for white skin in a cadaveric skin study by Kaidbey and colleagues. Furthermore, in a more recent study by Yamaguchi and co-workers, UV-induced apoptosis was found to be greater in the epidermis of black skin compared with white skin, suggesting that photodamaged cells may be removed more efficiently in darker phototypes.

In a comparative study by Nouveau-Richard et al of Chinese and French women, the onset of facial wrinkles was found to be approximately 10 years later in Chinese versus French women. Other studies in African-Americans have reported similar findings of later onset of facial rhytides or fine lines; Grimes found a much lower percentage of women of color perceived having wrinkles than did their Caucasian counterparts. In general, signs of facial aging in darker skin occur 10–20 years later than in Caucasians, and is more often evident in the deeper muscular layers in the face.

Loss of volume in the mid-face and prominent tear troughs have also been reported to be more striking features of aging in African-Americans. Perioral rhytides are uncommon in darker skin types and therefore the upper face is the primary site of facial rhytides in patients with skin of color. Photoaging differences in Hispanics / Latinos are less well characterized, but vary considerably, given the broad range of Fitzpatrick skin types (I–VI) found in this population.

Safety and efficacy of botulinum toxins in darker skin types

The safety and efficacy of botulinum neurotoxin type A in the treatment of glabellar lines has been well studied in numerous populations (Table 21.1). Published data pertaining to the safety and efficacy of botulinum toxin in non-white patient populations are reviewed herein.

Table 21.1 Published studies of botulinum toxin in darker skin types

A multicenter, double-blind, placebo controlled study of onabotulinumtoxinA (onabot-A) (Botox Cosmetic^®, Allergan, Inc., Irvine, CA) by Carruthers and colleagues in 2002 investigated safety and efficacy in the treatment of glabellar lines in 409 patients. No appreciable differences were observed between various skin phototypes.

African-Americans

Grimes & Shabazz conducted a Phase IV study of onabot-A in the treatment of glabellar lines in 31 African-American women with Fitzpatrick skin types V and VI. The authors assessed the safety and efficacy at doses of 20 and 30 units (U) of onabot-A. No statistically significant differences in efficacy or safety were observed between the two doses (Figs 21.1, 21.2). A maximal response was observed on day 30, with 92.4% and 100% response rates (i.e. a score of ‘none’ or ‘mild’ on the facial wrinkle scale) in the 20 U and 30 U groups respectively. Adverse events were mild and transient and did not differ between the dosing groups. They included mild tingling, slight headaches, and dullness of the forehead.

Figure 21.1 Glabellar rhytides at maximum frown in patient injected with 30 U botulinum toxin type A at: (A) baseline, (B) day 30, (C) day 60, (D) day 90, (E) day 120.

Reproduced with permission from Grimes PE, Shabazz D A four-month randomized, double-blind evaluation of the efficacy of botulinum toxin type A for the treatment of glabellar lines in women with skin types V and VI. Dermatol Surg. Mar 2009; 35(3):429–436.

Figure 21.2 Glabellar rhytides at maximum frown in patient injected with 20 U botulinum toxin type A at: (A) baseline, (B) day 30, (C) day 60, (D) day 90, (E) day 120.

Reproduced with permission from Grimes PE, Shabazz D Mar 2009 A four-month randomized, double-blind evaluation of the efficacy of botulinum toxin type A for the treatment of glabellar lines in women with skin types V and VI. Dermatol Surg 35(3):429-436.

In a Phase III study by Kane and colleagues of abobotulinumtoxinA (abobot-A) (Dysport^®, Medicis Aesthetics, Phoenix Arizona) for the correction of moderate to severe glabellar lines, no significant racial / ethnic differences in overall safety were observed using total doses of 50, 60, or 70 units for women and 60, 70, or 80 units for men in a single treatment. However, abobot-A-treated African-American patients had a slightly higher rate of ocular adverse events (6% for African-Americans versus 4% for other ethnicities) and a lower rate of injection-site reactions (3% versus 5% for other ethnicities). With respect to efficacy, the response rates and duration of action of abobot-A were found to be slightly higher in African-American subjects. Specifically, the median duration of action by blinded investigator evaluation was 117 days and 109 days for African-Americans and the overall population, respectively.

The reproducibility and potential etiology of these observed differences in African-Americans warrant further study.

Pearl 1

Appropriate magnification of injection sites is important to avoid vessels in darker skin types.

Pearl 2

Some patients are fearful of the procedure so consider avoiding multiple injections of anatomical sites during the first procedure. Allow the patient time to acclimatize to botulinum toxin injections.

Pearl 3

Very small doses of onabotulinumtoxinA (4 units), may improve crow’s feet in African-American women.

Asians

A multicenter, randomized, double-blind, placebo-controlled study by Harii & Kawashima of 142 Japanese subjects compared the safety and efficacy of 10 U versus 20 U onabot-A in the treatment of glabellar lines. Response rates in each active treatment group (10 U and 20 U) differed significantly from placebo (86.4% and 88.6%, respectively, versus 0% in the placebo group), but not from each other. The incidence of adverse events did not differ significantly between groups. An open-label, randomized, 64-week study by the same group involved 363 Japanese subjects and evaluated the safety and efficacy of repeated (up to five) treatments of 10 U and 20 U of onabot-A. The 20 U dose resulted in a significantly longer duration of effect than 10 U (17.1 ± 6.58 weeks and 14.8 ± 5.38 weeks respectively) and greater subject satisfaction without any significant differences in treatment-related adverse events.

An open-label study of 38 Korean patients by Ahn and co-workers evaluated the efficacy and safety of onabot-A in this population. Injections of 5–10 U were injected into the lateral canthal area, glabellar region, forehead, and / or nasal dorsum (depending on the individual patient’s wrinkle status) and the number of treatment sessions per subject ranged from 1 to 4. Approximately 69% of the patients had a duration of response of 13 weeks or more. Unexpected or ethnic-specific adverse events were not observed. In another Korean study by Lew et al, subjects were randomized to receive onabot-A (n = 14) or abobot-A (n = 6) and monitored 6–12 months post-treatment. Sites of injection included the lateral canthi, glabella, forehead, nasal dorsum, and nasolabial fold area. Both botulinum toxins demonstrated a comparable degree and duration of effect and were well tolerated.

A small randomized, double-blind, placebo-controlled, split face study by Chang and colleagues involving nine Taiwanese subjects evaluated the ‘face-lifting’ and wrinkle-reducing effect of onabot-A injected into the middle and lower face. No significant face-lifting effects were observed, but moderate wrinkle reduction was observed without unexpected or ethnic-specific treatment related adverse events.

Brazilians

The adjunctive use of onabot-A for the treatment of perioral vertical wrinkles in Brazilian subjects (Fitzpatrick skin types II–IV) was investigated in a randomized, double-blind, intrapatient controlled study by Kadunc et al (n = 12). Subjects with moderate to severe vertical rhytides of the upper lip were randomized to receive onabot-A or saline (control) at the vermilion border followed by chemabrasion with 35% trichloroacetic acid and manual dermabrasion 7 days’ post-injection. Transient postinflammatory hyperpigmentation occurred in 33% (4/12) of subjects and this was observed in subjects with higher Fitzpatrick skin types – Type III (n = 2) and Type IV (n = 2). Significantly less wrinkling (on the Facial Wrinkle Severity scale) was seen from day 90 to year 3 in the onabot -A-treated sides than in placebo.

Ethnic specific applications of botulinum toxin

As with any cosmetic procedure, taking into consideration a patient’s individual aesthetic ideals (which may, in turn, be influenced by culture and ethnicity) is paramount. Making broad generalizations about specific approaches that should be employed for a given racial / ethnic group can be problematic as can imposing Occidental aesthetic ideals on all patients regardless of their ethnicity. Notwithstanding these caveats, certain aesthetic goals can be observed more frequently in specific racial / ethnic groups and contribute to variations in the specific uses of botulinum toxin in patients of different backgrounds.

In East Asian populations the desire to have a wider and rounder appearance of the eye is common. Botulinum toxin is a popular non-invasive option for widening the palpepral aperture in that population. As reported by Flynn et al, treating the lower eyelid with 2 U of onabot-A (into the orbicularis oculi in the mid-pupillary line 3 mm below the ciliary margin) combined with 12 U in the crow’s feet, can produce an approximately 3 mm widening of the palpebral aperture at full smile and is a useful approach in addressing this concern in East Asians.

The lower third of the face is frequently wider in East Asians compared with Caucasian due to a larger mandibular width and / or hypertrophy of the masseter muscle. However, many East Asian women consider a more oval facial contour more aesthetically pleasing and seek cosmetic treatments to reduce the appearance of a square-shaped face. Reducing masseter hypertrophy using botulinum toxin is a popular procedure to achieve this goal, especially among Korean women. A study by Kim et al of 121 female patients in Korea treated with 100–140 U of abobot-A to the masseter muscle bilaterally demonstrated a decrease in masseter thickness by ultrasonography, which correlated with the number of treatment sessions.

Contouring of the calves using botulinum toxin is a popular procedure in Korean women. An ovoid shaped calf is commonly described as ‘radish-like leg’ in Korean and is frequent cosmetic concern in that population. Studies by Kim et al and Lee et al have demonstrated safety and efficacy of botulinum toxin for the treatment of enlarged gastrocnemius muscles in Koreans.

Conclusion

Given extensive published data demonstrating similar safety and efficacy in darker skin populations as seen in Caucasians, individual variations in muscle anatomy are more important than skin type or racial / ethnic background in the context of treating patients with botulinum toxin for facial aesthetic concerns. As a general rule, tailoring each treatment to a given patient’s individual anatomy and aesthetic goals (rather than relying on broad generalizations about racial or ethnic facial features) is the best strategy to employ when injecting neurotoxins. However, some ethnic specific variations in common aesthetic concerns exist, and these, in turn, contribute to unique applications for botulinum toxins in certain populations. Understanding these nuances in aesthetic ideals and the specific techniques to address them is increasingly important given the growing diversity of the patient population seeking cosmetic treatments with botulinum toxins.

Further reading

Ahn J, Horn C, Blitzer A. Botulinum toxin for masseter reduction in Asian patients. Archives of Facial Plastic Surgery. 2004;6(3):188–191.

Ahn KY, Park MY, Park DH, et al. Botulinum toxin A for the treatment of facial hyperkinetic wrinkle lines in Koreans. Plastic and Reconstructive Surgery. 2000;105(2):778–784.

Carruthers JD, Glogau RG, Blitzer A. Advances in facial rejuvenation: botulinum toxin type a, hyaluronic acid dermal fillers, and combination therapies – consensus recommendations. Plastic and Reconstructive Surgery. 2008;121(5 suppl):S5–S30. quiz S31–S36

Carruthers JA, Lowe NJ, Menter MA, et al. A multicenter, double-blind, randomized, placebo-controlled study of the efficacy and safety of botulinum toxin type A in the treatment of glabellar lines. Journal of the American Academy of Dermatology. 2002;46(6):840–849.

Chang SP, Tsai HH, Chen WY, et al. The wrinkles soothing effect on the middle and lower face by intradermal injection of botulinum toxin type A. International Journal of Dermatology. 2008;47(12):1287–1294.

Davis EC, Callender VD. Aesthetic dermatology for aging ethnic skin. Dermatologic Surgery. 2011;37(7):901–917.

Flynn TC. Periocular botulinum toxin. Clinical Dermatology. 2003;21(6):498–504.

Flynn TC, Carruthers JA. Botulinum-A toxin treatment of the lower eyelid improves infraorbital rhytides and widens the eye. Dermatologic Surgery. 2001;27(8):703–708.

Grimes P. Skin of color. Diseases and cosmetic issues of major concern. Cosmetic Dermatology. 2003;16:1–4.

Grimes PE, ed. Aesthetics and Cosmetic Surgery for Darker Skin Types, 1st edn, Philadelphia: Lippincott Williams & Wilkins, 2004.

Grimes PE, Shabazz D. A four-month randomized, double-blind evaluation of the efficacy of botulinum toxin type A for the treatment of glabellar lines in women with skin types V and VI. Dermatologic Surgery. 2009;35(3):429–436.

Han KH, Joo YH, Moon SE, et al. Botulinum toxin A treatment for contouring of the lower leg. Journal of Dermatologic Treatment. 2006;17(4):250–254.

Harii K, Kawashima M. A double-blind, randomized, placebo-controlled, two-dose comparative study of botulinum toxin type A for treating glabellar lines in Japanese subjects. Aesthetic Plastic Surgery. 2008;32(5):724–730.

Harris MO. The aging face in patients of color: minimally invasive surgical facial rejuvenation – a targeted approach. Dermatologic Therapy. 2004;17(2):206–211.

Hexsel DM, Hexsel CL, Brunetto LT. Botulinum toxin. In: Grimes PE, ed. Aesthetics and Cosmetic Surgery for Darker Skin Types. 1st edn. Philadelphia: Lippincott Williams & Wilkins; 2008:214–215.

Kadunc BV, Trindade DEAAR, Vanti AA, et al. Botulinum toxin A adjunctive use in manual chemabrasion: controlled long-term study for treatment of upper perioral vertical wrinkles. Dermatologic Surgery. 2007;33(9):1066–1072. discussion 1072

Kaidbey KH, Agin PP, Sayre RM, et al. Photoprotection by melanin – a comparison of black and Caucasian skin. Journal of the American Academy of Dermatology. 1979;1(3):249–260.

Kane MA, Brandt F, Rohrich RJ, et al. Evaluation of variable-dose treatment with a new U.S. botulinum toxin type A (Dysport) for correction of moderate to severe glabellar lines: results from a phase III, randomized, double-blind, placebo-controlled study. Plastic and Reconstructive Surgery. 2009;124(5):1619–1629.

Kawashima M, Harii K. An open-label, randomized, 64-week study repeating 10- and 20-U doses of botulinum toxin type A for treatment of glabellar lines in Japanese subjects. International Journal of Dermatology. 2009;48(7):768–776.

Kim NH, Park RH, Park JB. Botulinum toxin type A for the treatment of hypertrophy of the masseter muscle. Plastic and Reconstructive Surgery. 2010;125(6):1693–1705.

Lee HJ, Lee DW, Park YH, et al. Botulinum toxin a for aesthetic contouring of enlarged medial gastrocnemius muscle. Dermatologic Surgery. 2004;30(6):867–871. discussion 871

Lew H, Yun YS, Lee SY, et al. Effect of botulinum toxin A on facial wrinkle lines in Koreans. Ophthalmologica. 2002;216(1):50–54.

McKnight A, Momoh AO, Bullocks JM. Variations of structural components: specific intercultural differences in facial morphology, skin type, and structures. Seminars in Plastic Surgery. 2009;23(3):163–167.

Nouveau-Richard S, Yang Z, Mac-Mary S, et al. Skin ageing: a comparison between Chinese and European populations. A pilot study. Journal of Dermatologic Science. 2005;40(3):187–193.

Rossi A, Alexis A. Cosmetic procedures in skin of color. Giornale Italiano di Dermatologia e Venereologia. 2011;146(4):265–272.

(website) www.surgery.org

Yamaguchi Y, Beer JZ, Hearing VJ. Melanin mediated apoptosis of epidermal cells damaged by ultraviolet radiation: factors influencing the incidence of skin cancer. Archives of Dermatological Research. 2008;300(suppl 1):S43–S50.

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