Laser treatments on darker skin tones effective with conservative approach
Cutaneous laser therapy can prove to be challenging in treating patients with skin of color, as this patient population has a higher risk of unwanted cosmetic side effects following treatment. A cautious and conservative approach and use of the right laser device can be instrumental in helping to avert unwanted side effects from laser therapy.
"The increased melanin can potentially pose a greater risk of complications when undergoing cutaneous laser treatments, because the pigment can absorb the laser energy, leading to undesirable side effects, the most common of which being postinflammatory hyperpigmentation," says Henry Chan, M.D., Ph.D., F.R.C.P., F.H.K.C.P., F.H.K.A.M., honorary professor, Li Ka Shing Faculty of Medicine, University of Hong Kong, HKSAR, and visiting scientist, Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston.
According to Dr. Chan, the increased pigment content in the epidermis also absorbs some of the laser energy that one may want to use in deeper targets, such as the hair follicles in hair-removal procedures. When performing laser epilation, a cooling device is regularly used to protect the epidermis from the energy delivered down to the pigment cells around the hair follicle. However, due to the greater epidermal melanin content in patients with skin of color, the laser energy is more readily absorbed, reducing the efficacy of such laser treatments.
"Though an effective cooling is extremely important during and after the laser treatment, laser epilation treatments are less effective in patients with skin of color and are associated with a greater potential for complications," Dr. Chan says.
A similar problem is encountered when using lasers for the treatment of telangiectasias, as the melanin absorption of laser energy light sources has a very wide range. Therefore, lasers cannot only be less effective in the treatment of telangiectasias in patients with skin of color, but postinflammatory hyperpigmentation can also result, as well as interference by the superficial pigment in the epidermis, ultimately reducing the efficacy of the laser treatment.
POSSIBLE SOLUTIONS In order to avoid the unwanted side effects of laser treatments in patients with skin of color, it is very important to choose the proper parameters of the chosen laser device. It's also critical to apply adequate cooling during and after the laser procedure and to be less aggressive when performing therapy, particularly in higher-risk patients.
Devices such as Q-switched lasers are very effective in the removal of lentigines and freckles among Caucasians and Asians, but there is a 10 percent risk of postinflammatory hyperpigmentation in Asian skin. Therefore, these lasers can be less optimal for this indication in darker-skinned patients, and long-pulsed lasers may prove to be the better choice.
"Long-pulsed lasers are gentler than Q-switched lasers, because the Q-switched lasers induce not only a photothermal effect, but also the rapid change in the thermal gradient can lead to photomechanical damage, where the energy is delivered so rapidly that it literally causes the cells to rupture. Such damage can cause a greater risk of postinflammatory hyperpigmentation among skin of color," Dr. Chan explains.
Long-pulsed lasers are more effective mainly because they heat up the target more gradually and gently, reducing the excessive degree of inflammation and therefore decreasing the chance of adverse events. In order to maximize aesthetic outcomes and goals, more frequent treatment sessions would be required with this laser.
IPL AND FRACTIONAL DEVICES Intense pulsed light (IPL) is also effective for various cosmetic indications, even though the device is less selective in targeting specific lesions. According to Dr. Chan, IPL devices can work well depending on the contrast of the patient's skin in respect to the target lesions such as lentigines and freckles. IPL treatment is very effective and carries a low risk of adverse events if the patient's skin color is in great contrast with the color of targeted lesions. However, where the degree of contrast between the targeted lesions and the surrounding skin is much less, there will be a greater risk of injury.
"Either you use too low an energy not to negatively impact the surrounding skin, resulting in less-optimal treatment results, or too high an energy to effectively address the target lesions, with the increased risk of damaging the surrounding skin, leading to unwanted side effects. Therefore, one has to be extremely careful when treating patients with skin of color where the contrast between lesion and surrounding skin is low," Dr. Chan says.
Fractional resurfacing is frequently used for skin rejuvenation in Asian skin. However, given the fact that the degree and severity of photoaging tends to be much less in patients of skin of color, the role of these more aggressive ablative procedures (which carry a higher risk of complications) is much less justifiable, Dr. Chan says.
Noninvasive procedures such as radiofrequency and focus ultrasound for skin tightening are effective and very popular, as is nonablative skin rejuvenation using nonablative fractional resurfacing or nonablative laser devices.
LESS PHOTOAGING Compared to Caucasian skin, Asian skin tends to have much delay in terms of photoaging. Pigmentary issues such as lentigines, freckles and melasma are common problems after extensive ultraviolet (UV) light exposure, but, compared to Caucasian skin, deep wrinkles tend to present one to two decades later.
"The superficial epidermal melanin content in Asians is higher and therefore offers a greater UV protection — approximately 10 times that of Caucasian skin — and this protection increases with darker skin," Dr. Chan says. "As the degree and speed of skin aging is not as severe as that seen in Caucasian skin, we tend not to require extremely dramatic means to rejuvenate the skin."
For those physicians who do not regularly see patients with skin of color, Dr. Chan suggests that they treat a small test area of lesional skin with a given device first, and establish the correct parameters of the laser treatment in each patient before treating all lesions. Additionally, physicians with less experience with laser treatments in skin of color may want to begin with more forgiving devices, such as the long-pulsed laser.
"Remember to be conservative when performing laser procedures in skin of color. You do not want a patient to return because of potential issues and adverse events," Dr. Chan says.