Neil S. Sadick, MD, describes treating pigmentation in darker skin types using a 1064 nm picosecond pulse laser, avoiding the side-effects often attributed with energy-based devices
Inflammatory skin pigmentation, such as melasma or post-inflammatory pigmentation (PIH), can occur from a variety of triggers including side-effects of medications, allergic reactions, infections, trauma, inflammatory diseases, or as a complication of skin treatments with chemical peels, microdermabrasion, and energy-based devices such as ultrasound, radiofrequency, and laser/light devices1–3.
Briefly, the pathophysiology that drives the accumulation of melanin in the epidermis or dermis involves an inflammatory response that results in the release of cytokines causing melanocytes to overproduce melanin, disrupt its degradation, and increase its transfer to the surrounding keratinocytes. If the dermal basal layer is disrupted, melanin release is trapped in the papillary dermis by macrophages. Inflammation-induced pigment can occur in any individual regardless of their age and sex, but it is more common in individuals with darker skin (Fitzpatrick skin types III to VI)4. Excess localized pigment in cosmetically sensitive areas such as the face, arms and legs can cause a significant amount of emotional distress. Although pigmentation tends to fade with time (average 6–12 months) and treatment, recurrence is frequent, and flares can persist for years.
The main therapeutic strategies for treating pigmentation disorders are topical agents, chemical peels, laser/light energy devices or a combination of thereof. A topical agent such as hydroquinone is a first line choice of treatment for epidermal inflammatory pigmentation as it inhibits tyrosinase activity and expression, thereby inhibiting melanin synthesis. However, as it has limited efficacy for dermal pigmentation and causes irritation, it is not recommended as a long-term solution. Other topicals such as retinol creams, azelaic acid, and glycolic acid creams have the same drawbacks. Chemical peels, such as glycolic acid and salicylic acid, can artificially peel off the epidermis to remove melanin; however, aside from irritation they are not effective for dermal pigmentation and can cause dyschromias in patients of darker phototypes.
Laser and light treatments
Laser and light-based treatments have been routinely utilized to treat pigmentation, but none has been consistently effective to become a gold standard of treatment. Intense pulsed light (IPL), 1064 nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, 532 nm Q-switched Nd:YAG laser, Q-switched ruby laser, a 1550 nm erbium-doped fractional laser, and fractional carbon dioxide (CO2) lasers have all been studied to clear pigment and results have been invariably positive5,6. Q-switched (QS) lasers that deliver exceptionally high energy laser pulses with pulse durations in the nanosecond range have emerged as the most promising lasers for treating pigmentation, as they have been shown to effectively break down melanin without severe side-effects, as their mechanism of action relies on both photothermal and photoacoustic effects7. However, again, particularly in individuals with dark skin color, there is increased risk of post-inflammatory pigmentation and settings have to be lowered, compromising their efficacy. The risk is reduced with the use of longer-wavelength lasers (e.g., 1064 nm Q-switched Nd:YAG), that due to their ability to penetrate in the dermis, can treat dermal or mixed type pigmentation.
Recently, picosecond lasers, initially designed to treat tattoos of every color, have been evaluated for treating pigmentation; as they deliver pulses that are less than a nanosecond, their extremely short pulse duration creates more of a photoacoustic effect than a photothermal effect on targeted tissue. This short pulse duration enables these devices to treat even smaller particles than nanosecond lasers, use much less energy, and confine thermal damage to a much greater degree, and thus safely treat patients of all skin types8,9. Picosecond lasers are available in a variety of wavelengths, including lasers that emit wavelengths of 755 nm; 532, 680, and 1064 nm; and 532, 785, and 1064 nm. In addition, many of the picosecond devices have special applicators that can fractionate the laser beam and effectively eliminate superficial hyperpigmentation. As such, there is a growing sentiment amongst the clinical community that these lasers may become preferred over their Q-switched nanosecond counterparts for a variety of pigmentary dermatologic conditions.
In the author’s practice, they recently started using the enlighten™ laser (Cutera, Brisbane, CA) to treat pigmentation (PIH, melasma) and revitalize the skin in one session. The enlighten™ laser is an Nd:YAG picosecond laser system that treats tattoos and pigmented lesions at wavelengths of 532nm, 670nm and 1064nm (Figure 1). In addition to the three wavelengths, the device offers both picosecond and nanosecond pulse durations to treat all colors of tattoo, as well as benign pigmented lesions (BPLs) and skin revitalization. Due to its increased energy delivery per treatment, clinical endpoints can be achieved with lower fluences, in fewer sessions, thus minimizing the risk of scarring and reducing damage to surrounding skin structures from thermal burn. Moreover, by using dual wavelengths and the picosecond pulse duration, both pigment resolution and skin revitalization can be achieved in all skin types, a treatment known as picotoning. Although there are no published clinical studies to date using the enlighten laser simultaneously for pigment and skin rejuvenation, Stankiewicz et al. completed a case series with 10 female patients with Fitzpatrick skin types (FST) II-IV who had visible evidence of dyschromia, photo-damage, or photo-aged skin. Patients received three treatments at 4 to 6-week intervals using the 670 nm and 1064 nm wavelengths of the enlighten laser. During treatment, individual lesions were targeted using the 670 nm with no overlap to address dyschromias, followed by global treatment of the face using 1064 nm with low fluence and four to five passes. No cases of hypo- or hyperpigmentation were noted, and patients reported high levels of satisfaction and improvement in both pigmentation and skin quality10.
Similar to these results, the author has treated several patients so far, that request resolution of both their pigmentation and photoaging, with the picosecond dual pulsed 1064 nm enlighten™ laser. Typically, no topical anesthetic is required as treatments are not particularly painful unless the patients have a very low pain threshold in which case the skin is numbed by applying EMLA® cream (lidocaine 2.5% and prilocaine 2.5%) covered by an occlusive dressing for 45 minutes before being washed off. In Figure 2, the author highlights a 47-year old patient with skin type IV, that suffered from mixed type melasma. She had previously been treated with topicals (hydroquinone) and fractional non-ablative laser, but the pigment had returned within 3 months. She was treated with the enlighten™ laser using the 1064 nm wavelength (1064 nm, 0.6 J/cm2, 5 Hz, 8 mm x 4 passes). The patient did not experience any side-effects other than transient erythema. At the 4-week follow up, according to the treating physician there was a 50% reduction in the level of pigmentation, as well as global improvement of skin quality (Figure 2b). The patient reported a high level of satisfaction both regarding the pigmentation as well as the overall skin quality. Another patient, presenting with skin type III, had signs of photoaging as well as epidermal melasma (Figure 3a). She had not received any previous treatment for these indications. She was treated with the enlighten™ laser using the 1064 nm wavelength (1064 nm, 0.6 J/cm2, 5 Hz, 8 mm x 8 passes). No side-effects were reported, and at the 6-week follow up, there was evident clearance of both the pigment as well as improvement of the skin tone (Figure 3b). Both patients were scheduled to receive two additional treatments in 4–6 week intervals.
Initially, FDA-approved for the treatment of tattoos, picosecond lasers are emerging to be a new workhorse in the dermatologic practice, that treats a variety of dermatologic and aesthetic concerns. By toggling the wavelengths depending on the patient’s skin type, a full facial revitalization can be achieved, together with the treatment of specific pigment lesions, such as brown spots, melasma, and PIH. In the author’s clinic, patients that traditionally would be treated with QS-1064 nm or non-ablative fractional lasers, are now being treated with enlighten™. Of course, although there is no data yet on the long-term efficacy of the laser, and incidence of potential recurrence, both patients and physicians report high-level of satisfaction with the clinical experience. Treatments are short, and side-effects are minimal. The author envisions that in the next few years there will be a surge of clinical publications using picosecond lasers for pigmentation disorders and revitalization. Combination strategies and protocols are also likely to be developed using these lasers in conjunction with topicals or other energy-based devices, such as microneedling, to maximize the positive clinical outcomes in more complex and challenging clinical cases.