EXPERT ANALYSIS FROM AAD 17
ORLANDO (FRONTLINE MEDICAL NEWS) – With its unique tendency to develop postinflammatory hyperpigmentation (PIH), Latino skin needs a gentle touch from powerful lasers, according to Eduardo Weiss, MD.
“It’s often best to use a lower power, even though you trade off some efficacy for safety,” said Dr. Weiss, a dermatologist in Miami. “In general, it’s better to go with less aggressive treatment and more sessions, than to risk getting too aggressive and having a bad outcome.”
Dr. Weiss stressed that there are no “one size fits all” recommendations about laser treatment in typical Latino skin, because there’s no such thing as typical Latino skin. The group comprises all Fitzpatrick phototypes. But, in general, he said, the darker the skin, the greater the chance of an acute laser-induced burn, postinflammatory hyperpigmentation, and scarring.
This makes sense when viewed in the context of skin biology and laser mechanics. “Epidermal melanin acts as a competing chromophore, which can decrease the effect of the laser treatment and cause nonselective thermal injury to the epidermis,” Dr. Weiss said. “In darker-skinned individuals, there is an increase in the number and size of melanin granules within the basal layer keratinocytes. This large amount of melanin within the epidermis competitively absorbs laser light targeted for other chromophores. With the broad absorption spectrum of melanin, ranging from 250 nm to 1,200 nm, greater care and diligence must be taken when using lasers on Latino skin.”
Although general skin tone can provide a good first guess about the potential for hyperreaction to lasers, Dr. Weiss bolsters his judgments with a very simple – but effective – screen: palmar and digital crease pigmentation. First suggested by Hector G. Leal-Silva, MD , of the Institute of Dermatology and Cosmetic Surgery, Monterrey, Mexico, the screen divides patients into four groups, depending on the concentration of pigment present in palmar creases. A score of 0 means no pigment is visible, and the risk of PIH is negligible; a score of 3 means the creases are highly pigmented, and that the risk of PIH is very high.
But, with some adjustments in delivery – including using longer wavelengths and pulse duration, lower fluence and density, and smaller spot sizes – lasers can be used safely and effectively in these at-risk patients, Dr. Weiss said.
Safe treatment starts with pretreatment. It’s best to avoid laser procedures during the summer, when skin is at its darkest. Dr. Weiss also recommends a 6-week regimen aimed at lightening the area to be treated. This can include:
About a month before the procedure, he performs a test spot with the intended laser and its planned settings, in the preauricular area. Any PIH will be obvious within 2-4 weeks. He also carefully screens patients or any photosensitizing condition, like lupus or herpes simplex, or a history of any photosensitizing drugs, such as tetracycline.
Dr. Weiss made specific suggestions for laser treatment of some common Latino skin issues:
Pigmented lesions
The high density of epidermal melanin in Fitzpatrick types IV-VI acts as a competitive chromophore against hemoglobin and oxyhemoglobin. This makes it quite challenging to treat vascular lesions such as port wine stains and telangiectasias, he said. The pulsed dye laser is a good choice, with wavelengths of 585-590 nm especially effective. “The longer 595-nm wavelength allows for a slightly deeper penetration,” Dr. Weiss said. “However, the absorption coefficient of oxyhemoglobin is three times higher at 585 nm than [at] 590 nm.”
Longer pulses are generally safer in dark-skinned patients, he noted. “It will be much less effective than the 585, but for darker-skinned patients, we must sacrifice a little efficacy for safety.”
For rosacea and telangiectasias, Dr. Weiss suggests a 515-nm intense pulsed light with pulse duration of 12-15/ms for these lesions, or pigmentation, he also uses 540 nm or 500-600 nm with pulse duration of 12-15/ms.
Melasma, a very common condition in dark-skinned Latinos, is also “one of the most difficult and frustrating conditions to manage,” he pointed out. He turns to a laser only when the case is resistant to more conservative treatment, which typically includes Kligman’s formula, sunscreen, light peels, and azelaic or kojic acid.
“Lasers are still controversial and, in my opinion, a last resort for melasma. I wouldn’t start unless everything else fails. I reserve them for the deep nonresponding melasmas.”
The Q-switched Nd:YAG is the most widely used for melasma. The fluence used is less than 5 J/cm2, with a 6-mm spot size and a frequency of 10 Hz. The number of treatment sessions varies from 5 to 10 at 1-week intervals, Dr. Weiss said. “Keep in mind that rebound hyperpigmentation could be due to the multiple subthreshold exposures that can stimulate melanogenesis in some areas.”
Skin rejuvenation
Ablative lasers – long the gold standard for skin rejuvenation in those with light skin – can be problematic for darker-skinned patients, Dr. Weiss said.
“These lasers, like the CO2 and Erbium:YAG, can cause several unwanted side effects in Latino skin.” These can include hyperpigmentation, which occurs in 50% of Fitzpatrick III or higher phototypes; erythema that can last for months; and delayed-onset hypopigmentation.
“I think better options for our darker-skinned patients are nonablative infrared, microneedling, and radiofrequency devices,” Dr. Weiss said. “There are, however, newer microablative resurfacing lasers. Fractional CO2, fractional Erbium, and the 2,790-nm yttrium scandium gallium garnet, offer a safer modality with which to treat skin types IV and above. Compared with the older-generation resurfacing lasers, the microablative lasers minimize the amount and duration of erythema and edema, which can last just 3-4 days.”
Dr. Weiss had no relevant financial disclosures.
