of hyperpigmentation due to other traumas, allergy to lidocaine, personal or family history of photosensitizing conditions (ie, lupus erythematosus), herpes simplex, and recent intake of tetracycline or isotretinoin. Strict photo avoidance is discussed as well as protective measures including application of >SPF60 and oral sun protective supplement intake such as Heliocare, an oral extract of the Polypodium leucotomos fern. We also recommend a 6-week regimen aimed at lightening the area to be treated. The pretreatment regimen includes the application of hydroquinone 4-8%, the Miami Peel (modified Jessner’s with kojic acid and hydroquinone), and/or Kligman’s formula. A test-spot with follow-up in 2-4 weeks is also encouraged one month prior to treatment. Lastly, antiviral and antibiotic therapy is prescribed to the patient depending on laser device and treatment location.Laser Science The main principle describing the use of laser therapy is the concept of the target chromophore (Figure 3). A chromophore is a substance that absorbs specific wavelengths depending on its absorption coefficient. The three main endogenous chromophores targeted in lasers procedures are melanin, hemoglobin, and water. Melanin and hemoglobin are major chromophores for visible and near-infrared light while water is a major chromophore for far-infrared spectrum. For tissue damage to ensue, a wavelength should be preferentially absorbed by the chromophore in the target tissue and not the surrounding tissue, which may cause undesired effects (ie, dyspigmentation, scarring). To ensure maximized heat delivery to the target chromophore and the least risk to surrounding tissue, the wavelength delivered in a pulse duration should be less than or equal to the thermal relaxation time (TRT) of the target, a principle known as selective photothermolysis.4 There are several laser parameters that when taken into consideration can attenuate the risk of hyperpigmentation and scarring, especially in mixed color tones. These parameters include longer wavelengths, longer pulse duration, lower fluence, lower densities (MTZ/cm2), efficient cooling (pre, concurrent, post) and smaller spot size.
Chromophore: Hemoglobin
Vascular lasers, when used at the appropriate setting, can treat both light and dark skin tones in the Latino population. The main vascular chromophore is oxyhemoglobin. Darker phototypes (IV–VI) have more epidermal melanin that acts as a competitive chromophore against hemoglobin and oxyhemoglobin, therefore caution must be taken when targeting vascular lesions. Table 1 outlines the lasers we use in our practice for vascular lesions following with a discussion of selected lasers and skin conditions.Pulsed Dye Laser The pulsed dye laser (PDL) is a treatment of choice for vascular lesions such as telangiectasias. The 585nm wavelength pulsed dye laser penetrates to a desired depth of approximately 1.2 millimeters (mm). The longer 595nm wavelength allows for a slightly deeper penetration; however, the absorption coefficient of oxyhemoglobin is 3 times higher at 585nm than 590nm. In our opinion, the 585nm pulsed dye laser is superior in treating the vascular lesions such as port wine stains. In addition, both wavelengths are suitable for lighter complexioned skin tones (phototype IV and lighter). For darker phototypes V and VI, longer wavelengths should be utilized for treatment of vascular lesions. In addition, longer pulse durations should be used as it is safer in darker-skinned individuals. Treatment recommendation for rosacea with telangiectasias include 515nm with pulse duration between 12-15 (milliseconds) ms or higher. Alternatively, rosacea with telangiectasias and pigmentation require 570nm with pulse duration between 12-15ms or 500-600nm with pulse duration between 12-15ms.Intense Pulsed Light While there are many Intense Pulsed Light (IPL) devices available, the newer generation of IPL devices are as safe and effective as lasers in the management of skin conditions in darker skin tones. The patient’s skin phototype and skin condition will determine the choice of suitable cut-off filters and therefore the spectrum of wavelengths to be emitted. The same principles that apply to lasers to reduce the risk of hyperpigmentation after treatment are also true with IPL. Figure 4 depicts improvement of vascular and pigmented lesions using the IPL device.
