Laser Treatment of Ethnic Skin

Summary of Key Features

• The use of lasers, lights and devices can be safe and effective in ethnic skin.

• Sun protection pre- and posttreatment, together with the use of bleaching agents and topical corticosteroids, may reduce the risks of postinflammatory hyperpigmentation.

• For patients undergoing laser treatment for melasma, sun protection is essential to disease management.

• Lasers and light sources with longer wavelengths target dermal pigmentation and are safer in ethnic skin to minimize damage to epidermal melanocytes.

• Diascopy during treatment of pigmented lesions reduces the risk of collateral vascular damage.

• While the 585/595 nm pulsed-dye laser (PDL) and 532 nm potassium titanyl phosphate (KTP) and lithium triborate (LBO) lasers have been shown to be safe in ethnic skin, the 1064 nm Nd:YAG may be preferred for treating vascular lesions given its longer wavelength because of less pigment absorption.

• Picosecond lasers are effective in targeting dermal pigment (Hori’s nevus, Nevus of Ota, tattoo pigment) and can be safe to use in ethnic skin.

• Lower fluences with increased treatment sessions are commonly required when using Q-switched lasers in ethnic skin. Longer treatment intervals are needed to minimize risks of both hyper- and hypopigmentation.

• Microneedling offers a minimally invasive alternative to laser therapy in ethnic skin with lower risks of dyspigmentation. However, multiple treatment sessions may be required.

• Fractional plasma radiofrequency devices are a new and emerging safe alternative to traditional lasers for treating scars, skin laxity and lines.

• Skin tightening devices are “color blind” devices and safe across all skin types with minimum to no direct effect on skin pigmentation.

• An important consideration prior to laser or light treatment is to identify the presence of body dysmorphic disorder.

Introduction

The 21st century marks a dramatic transformative change in the diversity of the US population. According to the Pew research center, it is estimated that the population will grow to 438 billion, with over 50% representing traditionally ethnic minorities (Asian, Black, and Hispanics) as a result of immigration and intermarriage. In dermatology, this is of particular importance in the care of ethnic skin patients. This diverse group more broadly encompasses African, African-American, Afro-Caribbean, Asian, Indian, Middle Eastern, Latin-X, and biracial/multiracial individuals. Their skin color falls into the Fitzpatrick skin type scale IV–VI, distinguished by their lower response to UV sun exposure.

Special consideration is needed in the treatment of cutaneous disease in patients with ethnic skin. Unique differences exist compared to skin types I–III patients. Ethnic skin contains numerous larger melanosomes with more melanin and stability that is dispersed broadly to individual keratinocytes compared to skin types I–III, where the melanosomes are smaller, less stable and are clustered close together. This difference in melanosome biology results in increased photoprotection in ethnic skin. It also creates a therapeutic challenge in managing skin disease in ethnic skin, where dyspigmentation is a significant concern and not uncommon complication of lasers.

Careful selection of lasers and settings is essential to preventing unwanted dyspigmentation as melanin is a bystander chromophore that challenges treatment in ethnic skin. The aim of this chapter is to explore the challenges of using laser and light-based therapies in ethnic skin and to provide guidance to the practicing dermatologist on how to optimize its safe use in ethnic skin. Clinical pearls, prevention, and management of complications will also be highlighted in this chapter.

Evaluating the Ethnic Skin Patient

It is critical that all patients undergo a complete history and exam prior to treatment. The history should include past experiences with procedures, any treatment complications, current practices for UV protection and most importantly, evaluate patient expectations for treatment. On exam, it is important to assess the skin in both the desired treatment area and to look for any signs of hyperpigmentation or keloid formation after surgical or traumatic injury in other areas which can be helpful in guiding expectations. The initial appointment should focus on correct diagnosis and evaluating whether the condition of concern can be treated appropriately with laser. Complementary tools can be helpful in confirming the diagnosis. Woods lamp or UV photography can be a useful tool to differentiate between epidermal and dermal pigment in patients with melasma. Diascopy and a dermatoscope may have a role in evaluating ambiguous lesions. For solitary lesions with concerning features on dermoscopy, a biopsy should be considered before proceeding with treatment.

Once the diagnosis is confirmed, a discussion on laser/light options and alternative treatment (neuromodulators, injectables) if appropriate should be completed. The decision to proceed with laser/light treatment is one that should be arrived at after considering patient expectations and the clinical diagnosis. Patient expectations include their primary concern, timeline for treatment results, costs, expected downtime and complications. A common patient misconception is that acne scars can only be treated when there are no active acne lesions. However, certain lasers such as the 650-millisecond 1064 nm Nd:YAG laser, are indicated for the treatment of active acne lesions.

Another challenge is management of melasma. The patient seeking treatment for melasma should be counseled that topical lightening agents and sun protection are primary therapies for melasma whereas laser is a secondary sometimes even tertiary treatment option after chemical peeling. The topical regimen remains a critical part of the treatment and maintenance of results. After these expectations are reviewed and there is an understanding of treatment goals, a detailed review of treatment and related complications should be completed during the informed written consent process. Patients should also be given an opportunity to have all questions answered and additional time to reflect if desired.

The history and initial evaluation also provide an opportunity to evaluate for any absolute or relative contraindications. An important consideration and possible contraindication is a patient with an excessive and pervasive preoccupation with imagined deformities or exaggeration of actual disease, meeting the criteria for body dysmorphic disorder (BDD). The nature of the contraindication should be evaluated on a case-by-case basis. In a review of 401 Caucasian, Asian, and black women by Marques et al., no statistically significant difference was found in preoccupations among Caucasians and black patients. However, when compared to Caucasians, Asian patients reported less concern with body shape and increased concern with skin color and hair type. Physician awareness of these unique differences is important in managing the ethnic skin cosmetic patient. Referral to a psychiatrist for treatment is often needed.

Relative contraindications to laser therapy include a recent history of keloids or hypertrophic scarring, active pregnancy, active inflammatory disease or infection at the treatment site, and immunocompromised state. Recent systemic retinoid use within the past 6 months should be considered for patients undergoing fully ablative laser resurfacing.

During the initial visit, a key part of the discussion should include patient expectations. During the examination, patients should be given an opportunity to highlight their concerns as those may differ from that of the physician. Realistic treatment goals should be set to address these patient concerns. This should include an estimate on the number of treatments needed to meet expectations. Additionally, counseling on post-procedure care should be completed. This should focus on sun protection during and up to 6 weeks after treatment given the higher risk of dyspigmentation in ethnic skin patients. Written guidelines on post-procedure care should be given, reinforcing the need for regular sunscreen use and topical steroids or bleaching agents if indicated. For patients undergoing laser treatment for melasma, sun protection is essential to disease remission.

After a formal evaluation and setting treatment goals, informed written consent should be obtained. This includes a review of procedure risks and benefits with an opportunity for the patient to have all questions answered. Treatment alternatives and complications can be reviewed at this time. Taking the consent form home before treatment allows for additional review time and can be reassuring for some patients.

Postinflammatory Hyperpigmentation

Postinflammatory hyperpigmentation (PIH) frequently ranks among the top 10 concerns in ethnic skin patients. It commonly occurs after inflammatory cutaneous eruptions including acne, folliculitis or various rashes. However, it can also be iatrogenic from minimally invasive interventions such as laser and other energy-based therapies. Patients typically present with ill-defined hyperpigmented macules or patches in the same distribution as the inciting inflammatory cutaneous eruption or in the same shape or pattern as the culprit device. Topical treatment remains the gold standard for treating PIH in ethnic skin patients. Initial treatment discussions should focus on ultraviolet (UV) sun protective measures with frequent application of a broad-spectrum sunscreen with SPF 30 or higher and strict sun avoidance during the treatment period and immediate posttreatment period. Physical blocking agents containing zinc oxide, titanium dioxide, and iron oxides are preferred as they also block visible light.

After a discussion on sun protective measures, topical lightening medications should be considered. Topical lightening agents commonly include retinoids, hydroquinone, topical corticosteroids, azelaic acid, tranexamic acid, and may also include brightening ingredients like kojic acid (authors’ choice of an over counter topical), niacinamide, ascorbic acid, or ferulic acid. Hydroquinone is the most commonly used lightening agent with the best evidence in ethnic skin. It can be used as monotherapy in formulations of 4% or higher as a prescription or 2% over the counter and it is well tolerated. Rare side effects include exogenous ochronosis, usually at higher concentrations, and with prolonged use. Today, hydroquinone is traditionally used in combination therapy in the triple cream (Kligman’s formula: 4% hydroquinone, mild-mid potency topical steroid and tretinoin).

Chemical peels and systemic medications (oral tranexamic acid) can also be used as a tertiary treatment after a patient has failed first- and second-line treatments with sun protection and topical lightening agents, respectively. In ethnic skin, superficial peels are preferred because of its low risk since injury is limited to epidermis. There are a wide variety of treatment options for procedure related hyperpigmentation in ethnic skin. It is paramount for clinicians to be familiar with the treatment options available for treating hyperpigmentation in ethnic skin given the not infrequent complication of PIH in ethnic skin patients treated with lasers and light therapy. This chapter will highlight ways to minimize risks of hyperpigmentation in ethnic skin patients through proper laser selection and settings.

Authors’ choice of treatment for procedure-related PIH:

• Superficial chemical peels: salicylic acid or mandelic acid every 3–4 weeks until resolution or until maximal effects have reached a clinical plateau

• Pretreating with 4% hydroquinone at least 2 weeks prior to treatment

• Posttreatment: a mid-potency topical corticosteroid for at least 3 days after treatment or a high-potency topical steroid for 2 days after treatment

Introduction to Lasers and Lights in Ethnic Skin

Lasers and energy-based therapy can offer an effective and fairly noninvasive method for treating signs of photoaging, dyspigmentation, scarring, and overall facial rejuvenation. In ethnic skin patients, unique challenges exist due to the not infrequent risk of post-procedure dyspigmentation because of the melanin-rich epidermis compared to nonethnic skin (skin types I–II). Procedure-related dyspigmentation can be a result of accidental melanin injury as a competing bystander chromophore or patient specific risk for PIH as part of the normal healing process. With proper training, more spaced-out treatment sessions and conservative laser settings, similar cosmetic outcomes are achievable for ethnic skin patients with the full spectrum of lasers being a safe and effective treatment option.

Laser selection should focus on identifying the proper target chromophore: water, hemoglobin or melanin, to achieve clinical goals. Other considerations for laser selection include the ability to modify settings for minimally invasive treatment. This can be achieved by using lower fluences. Another example of this includes the selection of ablative versus nonablative lasers. Ablative lasers offer quicker and more remarkable results but come with an increased risk of dyspigmentation due to the uniform sheet like destruction of the epidermis when compared to nonablative lasers that create microthermal zones, keeping most of the epidermis intact. Adjunctive tools can also be beneficial in minimizing dyspigmentation. The use of simple diascopy (glass slide compression of a blood vessel) moves blood away from the vessel lumen during vascular laser treatment (585/595 nm PDL) to decrease purpura and hyperpigmentation in ethnic skin patients without compromising treatment efficacy. With proper settings, adjunctive tools and appropriate laser selection, a wide spectrum of lasers can be available to ethnic skin patients including intense pulsed light (IPL). For IPL, lower energies with multiple passes and combining treatment with a cooling device can make it a safe option in these patients.