Laser Hair Removal in Ethnic Skin: Principles and Practical Aspects

By Amy J. McMichael MD and Vasanop Vachiramon MD

INTRODUCTION
Laser hair removal (LHR) has become an increasingly popular procedure during the past decade. In white skin, LHR is known and works with a fairly low number of treatments and relatively few side effects. In dark-skinned individuals, especially African-Americans, where the hair tends to be coarse and curly, dermatologic conditions such as pseudofolliculitis barbae and significant post-inflammatory hyperpigmenation often do not respond to conventional methods of hair removal. Thus, LHR can become a medical necessity for the treatment of unwanted hair in dark-skinned patients, for whom there may be few therapeutic alternatives.

BACKGROUND
Clinical Issues
When darker-skinned women present with unwanted facial hair, there is often significant post-inflammatory hyperpigmentation in the affected area. Conventional hair removal methods such as waxing, shaving, depilatories, and plucking often remove the hair, but can increase the development of perfollicular hyperpigmentation. In the clinical setting, dark-skinned women with complaints of hirsutism, accompanying hyperpigmentation, and pseudofolliculitis formation should first be evaluated for hormonal abnormality (Figure 1). Once this is ruled out, laser hair removal is the only hair removal technique that will allow treatment of large areas with safety and an ensuing decrease in population and pigmentation.

FIGURE 1. Hirsutism, pseudofolliculitis, and significant post-inflammatory hyperpigmentation in a 45-year-old African-American woman.

When a darker-skinned man presents with the primary complaint of significant papules, pustules and irritation in the beard area with shaving, the options are few for definitive treatment of these lesions. Laser hair removal in a limited number of treatments can offer significant improvement in all clinical complaints in the beard areas without extensive change in hair density, allowing men to retain the male look of facial hair. Here we describe the key points when dealing with LHR in darker-skinned patients. With these strategies, dermatologists and medical practitioners will be more confident when treating unwanted hair with laser.

SETTINGS AND METHODS
Before Treatment
Patients should be informed and understand the risks and benefits of treatment, long-term results, treatment alternatives, cost, and the possibility of treatment failure or potential recurrence of hair growth. In patients who are at high risk or particularly concerned about potential side effects, a laser test spot, preferably in or next to the planned treatment area, should be carried out. The test spot should be assessed for adverse reactions immediately after the treatment and 1–2 weeks later. In addition, patients with unrealistic expectations are not ideal treatment candidates.
In clinical practice, there are number of dark-skinned patients who still have negative attitudes and lack of knowledge about LHR despite safe treatment existing for more than 10 years. Data from a recent survey found that 15 of 221 (6.8%) African-American subjects surveyed had been told not to have LHR because of skin color and 44.8 percent of these subjects disagreed or were not sure whether dark-skinned people could be treated with LHR.1 Thus, it is important for dermatologists to give appropriate information during the initial consultation and emphasize the safety of LHR in dark-skinned patients.

During Treatment
The absorption coefficient of melanin is inversely correlated with the wavelength of the laser, i.e., epidermal melanin absorbs approximately four times as much energy when irradiated by a 694 nm ruby laser compared to the 1064 Nd:YAG laser.2 Therefore, dark-skinned patients should be treated with devices with a long wavelength (1064 Nd:YAG) rather than a wavelength that has a higher coefficent of absorption with epidermal melanin (e.g., Alexandrite).3

When determining treatment parameters, fluence is as important as the laser wavelength chosen when treating dark-skinned patients. Skin phototype VI may absorb as much as 40 percent more energy when irradiated by visible light laser than does skin phototype I or II when fluence levels and exposure duration are constant.4 Thus, the minimum fluence that produces the desired tissue effect in a given individual should be employed to minimize unnecessary damage of collateral tissue. In addition, the fluence should be lowered on highly dense hair-bearing areas (e.g., chest, back) to avoid non-selective damage through excessive heat diffusion.

The use of longer pulse duration (e.g., more than 30 ms) is recommended when treating dark-skinned patients.5 With longer pulse duration, the energy is transferred to the skin more slowly, and the epidermis absorbs the light slower and heats up slower, reducing epidermal injury. Effective cooling devices are essential when treating dark-skinned patients. Without epidermal cooling, the heat creates unwanted thermal injuries including blistering, scarring, and dyspigmentation. Most lasers are equipped with cooling devices (e.g., copper cooled tip, sapphire cooled tip, cryogen spray cooling) (Figure 2). In addition, external air cooling and cooling aqueous gel may be used adjunctively to minimize epidermal injury (Figure 3).

FIGURE 2. A built-in copper cooling device integrated into the tip of the laser handpiece.

FIGURE 3. External air cooling device.

After Treatment
Strict sun avoidance and daily use of broad-spectrum sunscreen is recommended to avoid further tanning of the treated sites. Patients should be made aware of what to expect postoperatively (e.g., transient erythema) and instructed to notify the office as soon as possible if an adverse reaction occurs.

Cautions
While conservative fluence settings should be employed in dark-skinned patients, it is still important to consider the endpoint, i.e., perifollicular edema and erythema. Too-low fluence settings can result in no therapeutic improvement. Excessive cooling should also be avoided as it can result in cold injuries (e.g., blistering, dyspigmentation).6,7

CLINICAL BOTTOM LINE
In conclusion, in this pearl we addressed important aspects of dealing with LHR in dark-skinned patients. The key points are to offer patients of color the option to have laser hair removal treatment if it is indicated (while recognizing that they may be under incorrect assumptions regarding safety) by using long wavelength, long pulse duration, conservative fluences, and effective epidermal cooling. The population of the United States is dramatically shifting in the 21st century. The majority of US populations will no longer have fair skin, but instead darker skin, also referred to as “skin of color.” This change will significantly impact the practice of dermatology. With this laser pearl, we hope that dark-skinned patients who are treated with laser hair removal will achieve a high satisfaction without complications after the procedure.

DISCLOSURES
The authors have no relevant conflicts of interest to disclose.

REFERENCES
1. Vachiramon V, McMichael AJ. Patient knowledge and attitudes on laser hair removal: A survey in people of color. J Cosmet Dermatol. 2011;10:197-201.
2. Alster TS, Tanzi EL. Laser surgery in dark skin. Skinmed. 2003;2:80-85.
3. Battle EF Jr, Hobbs LM. Laser therapy on darker ethnic skin. Dermatol Clin. 2003;21:713-723.
4. Anderson RR. Laser-tissue interactions in dermatology. In: Arndt KA, Dover JS, Olbricht SM, eds. Lasers in Cutaneous and Aesthetic Surgery. Philadelphia: Lippincott-Raven; 1997: 28.
5. Bhatt N, Alster TS. Laser surgery in dark skin. 2008;34:184-194, discussion 94-95.
6. Datrice N, Ramirez-San-Juan J, Zhang R, Meshkinpour A, Aguilar G, Nelson JS, et al. Cutaneous effects of cryogen spray cooling on in vivo human skin. Dermatol Surg. 2006; 32:1007-1012.
7. Manuskiatti W, Eimpunth S, Wanitphakdeedecha R. Effect of cold air cooling on the incidence of postinflammatory hyperpigmentation after Q-switched Nd:YAG laser treatment of acquired bilateral nevus of Ota like macules. Arch Dermatol. 2007;143:1139-1143.

About the author

Amy J. McMichael MD and Vasanop Vachiramon MD

Amy J. McMichael MD, Wake Forest University School of Medicine, Winston-Salem, NC and Vasanop Vachiramon MD, Department of Dermatology, Ramathibodi Medical School, Mahidol University, Bangkok, Thailand

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