Comparative study of treatment efficacy and the incidence of post-inflammatory hyperpigmentation with different degrees of irradiation using two different quality-switched lasers for removing solar lentigines on Asian skin

Efficacy of isobutylamido thiazolyl resorcinol for prevention of laser-induced post-inflammatory hyperpigmentation: A randomized, controlled trial

BACKGROUND

Q-switched (QS) Nd: YAG laser is one of the treatment options for solar lentigines (SLs). However, the incidence of post-inflammatory hyperpigmentation (PIH) is a common complication, especially in dark-complexioned skin. Isobutylamido thiazolyl resorcinol (ITR) has been reported as a preventive modality for ultraviolet B (UVB)-induced hyperpigmentation.

AIMS

This study aims to evaluate the efficacy and safety of ITR for the prevention of laser-induced PIH.

PATIENTS/METHODS

A randomized, evaluator-blinded study including 24 subjects with SLs was conducted. Three SLs of each patient were randomized into three groups, which were to apply ITR twice daily, once daily, and no application for 2 weeks. Thereafter, 532-nm QS Nd: YAG laser was performed. Incidence of laser-induced PIH, relative melanin index (RMI), mean luminance score (L*), hyperpigmentation score, and adverse events were recorded for 2 months post-laser.

RESULTS

The incidence of PIH at the 4th week after laser treatment was significantly lower in the ITR twice-daily group compared to the no-application group (20.83% vs. 50%, p = 0.028). There was no statistically significant difference in RMI, mean L*, and hyperpigmentation score between treatments at all visits. No serious adverse events were reported regarding ITR application and laser treatment.

CONCLUSION

Two-week application of ITR prior to QS: Nd YAG laser treatment may potentially reduce the incidence of PIH. A longer duration of application, including after the laser procedure, may be more beneficial for the prevention of laser-induced PIH.

Correlation between the efficacy of picosecond-domain laser treatment for solar lentigo and the vascularity in the upper dermis using optical coherence tomography angiography in Asian women

OBJECTIVES

The purpose of this study was to noninvasively confirm the characteristics of the dermal vasculature in patients with solar lentigo (SL) and determine any association with the efficacy of picosecond-domain laser (PSL) treatment.

METHODS

Thirteen facial SL lesions in 11 Asian female patients were included in this study and evaluated over 12 weeks. An Nd:YAG laser was used at 532 nm and 750 ps. Skin color and morphological structure were evaluated by ANTERA-3D® and optical coherence tomography (OCT), respectively. To analyze the vascularity in the upper dermis, an OCT angiography (OCTA) algorithm was applied to the OCT data.

RESULTS

After PSL treatment, significant improvement in both hyperpigmentation and abnormally thickened epidermis was observed, but the efficacy varied for each lesion. There was a significant correlation between the change in the melanin index due to PSL treatment and preoperative vascular density in the upper dermis.

CONCLUSIONS

To the best of our knowledge, this is the first report to demonstrate a correlation between the efficacy of PSL treatment of SL lesions and the vascularity in the upper dermis. Methods to evaluate the vasculature in the upper dermis may be useful for preoperative prediction of the efficacy of PSL treatment for SL lesions.

Commentary: Facial Aesthetic Dermatological Procedures and Photoprotection in Chinese Populations

The medical literature on aesthetic dermatology has primarily focused on a light-skinned patient population, yet patients of darker skin types have different needs and priorities. In Chinese individuals, key concerns include altered pigmentation, which is perceived to age the individual, and also relates to the Chinese cultural standard of beauty of fair skin; many seek aesthetic treatment for this. Non-invasive cosmetic procedures such as lasers and injections are also gaining in popularity in the Chinese market, but this population is prone to hyperpigmentation as an adverse effect of such procedures. Considered and tailored approaches, both to primary concerns of photoaging and the side effects of cosmetic treatments, are warranted.

A Randomized, Evaluator-blinded Comparative Study of a Potassium Titanyl Phosphate (KTP) 532-nm Picosecond Laser and an Alexandrite 755-nm Picosecond Laser for the Treatment of Solar Lentigines in Asians

BACKGROUND

Various pigment-specific lasers can be used to treat solar lentigines. However, the most effective treatment options remain to be explored to reduce complications, such as post-inflammatory hyperpigmentation, especially in dark-skinned patients.

OBJECTIVES

This study aims to compare the efficacy and safety between the KTP 532-nm picosecond laser and the alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians.

MATERIALS AND METHODS

Thirty patients who had at least two solar lentigines on their arms were enrolled. A total of 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532-nm picosecond laser or an alexandrite 755-nm picosecond laser. Mean luminance score (L*) was evaluated at baseline and at six, and 12 weeks to determine treatment efficacy. Improvement was assessed by a blinded physician using a 5-point score. Satisfaction was rated by patients using a visual analogue scale. All adverse events were documented.

RESULTS

All 30 patients completed the study. Both lasers showed significant improvement in mean L* from baseline (p<0.001). With the parameter settings employed, lesions treated with the alexandrite 755-nm picosecond laser showed greater improvement in mean L* when compared with treatment with the KTP 532-nm picosecond laser at 12 weeks follow-up (p=0.002). According to physician scoring, more than 50% improvement was observed in 25 and 19 lesions of the alexandrite 755-nm picosecond laser group and the KTP 532-nm picosecond laser group, respectively. Adverse events did not differ between groups. A significantly higher satisfaction score was observed with the alexandrite 755-nm picosecond laser at the last visit (p=0.038).

CONCLUSION

Both types of picosecond laser may be used to treat solar lentigines. Proper treatment settings and endpoint observation are the most important factor to achieve a successful outcome.

Blue Laser (450 nm) Treatment of Solar Lentigines

This study tested a blue light source for the treatment of solar lentigines. A total of 14 patients with solar lentigines were treated with radiation from a novel, high-power 450 nm blue laser that was created for this project. The group contained eight patients with solar lentigines on the face, two patients with the lesions on the dorsal of the hands, and four patients with the lesions on the trunk and forearms. The best results (complete recovery) have been achieved for the lesions on the face and dorsal of the hands. The treatment of lesions on the trunk and forearms was not fully satisfying due to the occurrence of slight scarring. This study shows that, in some cases, the use of a blue laser may be an alternative to the use of longer wavelength sources.

In vivo harmonic generation microscopy for monitoring the height of basal keratinocytes in solar lentigines after laser depigmentation treatment

The development of solar lentigines (SLs) is related to chronic ultraviolet exposure-induced cell senescence. We have previously demonstrated that basal keratinocyte enlargement is a morphological hallmark of skin senescence correlated to the process of skin aging, while clinical studies on the long-term monitoring of the cellular morphological changes in SLs after laser treatment are lacking. In this study, we have developed the harmonic generation microscopy (HGM) for in vivo monitoring the height of basal keratinocytes (HBK) and had administered Q-switched ruby laser or picosecond 532-nm Nd:YAG laser treatment on each side of the face of 25 Asian patients with facial SLs, respectively. In vivo HGM imaging was conducted to longitudinally analyze HBK and the horizontal cell size (HCS). Before treatment, the HBK was significantly higher in the SLs lesional area than that in the adjacent normal region, whereas there was no significant difference in the HCS. After treatment, the lesional HBK remained significantly higher than normal skin regardless of the laser treatment used. Our study indicates that the basal keratinocytes remain abnormal after laser treatment and demonstrates the capability of in vivo HGM for longitudinal, quantitative monitoring of cell senescence and therapeutic effect in SLs.

Treatment of facial and non-facial lentigines with a 730 nm picosecond titanium: Sapphire laser is safe and effective

Objective

A 730 nm picosecond‐domain laser was developed to improve the clearance of pigmented lesion and reduce adverse events. This study assessed the safety and efficacy of this system for the clearance of lentigines and explores how the short picosecond pulses interact with tissue via histology.

Study Design and Methods

Twenty subjects with Fitzpatrick skin types II–IV were enrolled in this prospective, IRB‐approved study. Four treatments were administered using a 730 nm picosecond‐domain laser. Pre‐ and posttreatment photos were assessed by blinded reviewers at 4‐ and 12‐week follow‐up visits, using a 5‐point clearance scale. Subject satisfaction was measured using a 5‐point scale. Investigator Global Improvement Score (IGIS) was performed at the 4‐ and 12‐week follow‐up visits, using an 11‐point clearance scale. Subject pain level was measured using an 11‐point scale (no pain [0], extreme pain [10]). Histology of 730 and 532 nm picosecond pulses was compared with 755 and 532 nm nanosecond pulses.

Results

Sixteen subjects with a total of 118 discontinuous treatment areas, each comprised of 1–20 lesions, completed all study visits. Thirty body regions were studied, including arms (6), hands (16), scalp (1), forehead (2), face (3), and back (2). Spot sizes ranging from 2 to 5 mm diameters were used with fluences ranging from 0.8 to 4.0 J/cm². Mean pain score was 3.6 of 10 for all four treatments. Ninety‐nine percent of randomly paired 4‐week posttreatment images and 100% of 12‐week posttreatment images were correctly identified from their respective baseline images by three blinded reviewers. Mean IGIS demonstrated scores of 6.7 and 7.0 at 4‐ and 12‐week follow‐up visits, respectively. At the 4‐ and 12‐week follow‐up visits, 76% and 73% of subjects, respectively, were satisfied to highly satisfied. The mean clearance score for all 118 treatment areas was 3 of 4 in follow‐up visits. At 12‐week follow‐up, 36% of 118 treatment areas had a clearance score of 4, and 38% had a clearance score of 3. Post treatment, there was typical erythema, edema, dryness, crusting, and itching but negligible purpura, no pinpoint bleeding, blistering or scarring, and no significant hyperpigmentation or hypopigmentation. Histology showed diffuse, focal epidermal vacuolization ~5–10 µm in diameter and mild extravasation of erythrocytes with 730 nm picosecond pulses, while diffuse epidermal vacuolization was observed with coalescence of vacuoles (~20–100 µm), junctional clefting and mild extravasation of erythrocytes with 755 nm nanosecond pulses. Picosecond pulses of the wavelength of 532 nm produced diffuse, focal epidermal vacuolization and larger dermal vacuoles to depths of 500 µm, while 532 nm nanosecond pulses produced diffuse epidermal vacuolization with coalescence of vacuoles and marked dermal hemorrhage.

Conclusion

This study demonstrated the potential of a new 730 nm picosecond‐domain laser for the clearance of lentigines. The results showed good clearance with no adverse events and good subject satisfaction in patients with skin type II–III. Additional studies need to be conducted on darker skin types. The histopathologic findings demonstrate that the picosecond 730 nm laser produces excellent selectivity for pigment with minimal disruption of the dermal–epidermal junction and may therefore reduce healing times and the risk of adverse events.

A Randomized Controlled Trial on the Effectiveness of Epidermal Growth Factor-Containing Ointment on the Treatment of Solar Lentigines as Adjuvant Therapy

Background and Objective: Little is known about the anti-pigmentation effects of whitening agents on solar lentigines. Epidermal growth factor (EGF) has been used as a booster for wound healing in the skin, and it has been suggested to have anti-pigmentation effects. This study aimed to evaluate the effect and safety of EGF-containing ointment for treating solar lentigines with a Q-switched (QS) 532 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (Bluecore company, Seoul, Republic of Korea). Materials and Methods: Subjects who underwent QS 532 nm Nd:YAG laser treatment of solar lentigines were randomly assigned to treatment with an EGF ointment or petrolatum. After the laser procedure, the subjects were administered the test ointment twice a day for 4 weeks. The physician's assessment of the degree of pigment clearance and patient's satisfaction were assessed after 4 and 8 weeks. Additionally, the melanin index (MI), erythema index (EI), transepidermal water loss (TEWL), and post-inflammatory hyperpigmentation (PIH) were evaluated. This trial was registered with ClinicalTrials.gov (NCT04704245). Results: The blinded physician's assessment using 5-grade percentage improvement scale and patient's satisfaction were significantly higher in the study group than in the control group at the 4th and 8th weeks. The MI was significantly higher in the control group than in the study group at the 4th and 8th weeks. The EI and TEWL did not differ significantly between the two groups at either time point. The incidence of PIH was higher in the control group (37.5%) than in the EGF group (7.14%) at the 8th week. Conclusions: The application of EGF-containing ointment on facial solar lentigines with a QS 532 nm Nd:YAG laser showed efficient and safe therapeutic effects, with less PIH. Thus, EGF-containing ointment could be suggested as the promising adjuvant treatment strategy with a QS laser for solar lentigines.

Clinical Evaluation of Safety and Efficacy of a 670-nm Picosecond Laser for Treatment of Benign Pigmented Lesions in Asians

BACKGROUND

Picosecond lasers are increasingly being investigated in treating pigmentation disorders because they may provide better treatment efficacy and comfort compared with nanosecond lasers.

OBJECTIVE

This study aims to evaluate the efficacy and side effect of a novel 670-nm picosecond laser in the removal of benign pigmented lesions (BPLs) in individuals with Fitzpatrick skin types (FST) III and IV.

MATERIALS AND METHODS

Fifteen subjects with solar lentigines and 7 subjects with ABNOMs received a single treatment with a 670-nm picosecond laser. Blinded physicians assessed the pigment clearance using a 5-category grading system scale. All subjects were evaluated at 1 month, 3 month, and 6 month after a single treatment. Adverse events were recorded at every follow-up visit.

RESULTS

All subjects with lentigines had complete clearance (95%-100%) of lesions during 3-month follow-up after a single treatment session of 670-nm picosecond laser, whereas 75% of the subjects with ABNOMs noted fair lightning (25%-49%) of lesions. Mild hypopigmentation and hyperpigmentation were observed in 9% and 14% of the subjects, respectively, which resolved within 3 months after the treatment.

CONCLUSION

The novel 670-nm picosecond laser is a safe and effective treatment for BPLs in subjects with FST III and IV with low rates of transient adverse effects.

Melanogenic Difference Consideration in Ethnic Skin Type: A Balance Approach Between Skin Brightening Applications and Beneficial Sun Exposure

Human skin demonstrates a striking variation in tone and color that is evident among multiple demographic populations. Such characteristics are determined predominantly by the expression of the genes controlling the quantity and quality of melanin, which can alter significantly due to the presence of small nucleotide polymorphism affecting various steps of the melanogenesis process and generally linked to the lighter skin phenotypes. Genetically determined, constitutive skin color is additionally complemented by the facultative melanogenesis and tanning responses; with high levels of melanin and melanogenic factors broadly recognized to have a protective effect against the UVR-induced molecular damage in darker skin. Long-term sun exposure, together with a genetic makeup responsible for the ability to tan or the activity of constitutive melanogenic factors, triggers defects in pigmentation across all ethnic skin types. However, sun exposure also has well documented beneficial effects that manifest at both skin homeostasis and the systemic level, such as synthesis of vitamin D, which is thought to be less efficient in the presence of high levels of melanin or potentially linked to the polymorphism in the genes responsible for skin darkening triggered by UVR. In this review, we discuss melanogenesis in a context of constitutive pigmentation, defined by gene polymorphism in ethnic skin types, and facultative pigmentation that is not only associated with the capacity to protect the skin against photo-damage but could also have an impact on vitamin D synthesis through gene polymorphism. Modulating the activities of melanogenic genes, with the focus on the markers specifically altered by polymorphism combined with differential requirements of sun exposure in ethnic skin types, could enhance the applications of already existing skin brightening factors and provide a novel approach toward improved skin tone and health in personalized skincare.

A Split-Face, Single-Blinded, Randomized Controlled Comparison of 532 nm Picosecond Neodymium-Doped Yttrium Aluminum Garnet Laser versus 532 nm Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser in the Treatment of Solar Lentigines

Background

Solar lentigines are the most common form of benign epidermal pigmentation and one of the major cosmetic concerns in Korea. A 532 nm Q-switched neodymium: yttrium-aluminum-garnet (QSND) laser is typically used for the treatment, but the occurrence of post-inflammatory hyperpigmentation (PIH) is not rare. Recently, the use of picosecond (PS) lasers has emerged in pursuit of better outcomes.

Objective

To objectively compare the efficacy and safety of 532 nm PS and QSND lasers for the treatment of solar lentigines.

Methods

Twenty patients with solar lentigines were enrolled in a prospective, randomized split-face, single-blind study. One side of each face was treated using a 532 nm PS laser, and the other side using a 532 nm QSND laser. After one treatment, all patients were followed up for evaluation after 2, 4, 8, and 12 weeks. The clinical clearance was assessed by three blinded dermatologists using a 5-point quartile improvement scale (QIS). Subjective satisfaction, development of PIH, pain scale during treatment, and adverse problems were also recorded.

Results

Clinical clearance measured by QIS showed that the PS laser was more effective than the QSND laser. Subjective satisfaction and pain scale did not significantly differ between the two groups. The incidence of PIH was 5% in sides treated with the PS laser, and 30% with the QSND laser.

Conclusion

Both 532 nm PS laser and QSND laser were effective for the treatment of solar lentigines, but the PS laser was more effective with less PIH development.

Effect of urea-extracted sericin on melanogenesis: potential applications in post-inflammatory hyperpigmentation

Background

Hyperpigmentation disorders such as post-inflammatory hyperpigmentation are major concerns not only in light-skinned people but also in Asian populations with darker skin. The anti-tyrosinase and immunomodulatory effects of sericin have been known for decades. However, the therapeutic effects of sericin on hyperpigmentation disorders have not been well documented.

Methods

In this study, we used an in vitro model to study the anti-tyrosinase, tolerogenic, and anti-melanogenic effects of sericin on Staphylococcus aureus peptidoglycan (PEG)-stimulated melanocytes, dendritic cells (DCs), and artificial skin (MelanoDerm™). Enzyme-linked immunosorbent assay, conventional and immunolabeled electron microscopy, and histopathological studies were performed.

Results

The results revealed that urea-extracted sericin has strong anti-tyrosinase properties as shown by a reduction of tyrosinase activity in melanin pigments both 48 h and 10 days after allergic induction with PEG. Anti-inflammatory cytokines including interleukin (IL)-4, IL-10, and transforming growth factor-β were upregulated upon sericin treatment (10, 20, and 50 µg/mL), whereas production of allergic chemokines, CCL8 and CCL18, by DCs was diminished 48 h after allergic induction with PEG. Moreover, sericin lowered the expression of micropthalmia-associated transcription factor (MITF), a marker of melanogenesis regulation, in melanocytes and keratinocytes, which contributed to the reduction of melanin size and the magnitude of melanin deposition. However, sericin had no effect on melanin transport between melanocytes and keratinocytes, as demonstrated by a high retention of cytoskeletal components.

Conclusion

In summary, sericin suppresses melanogenesis by inhibition of tyrosinase activity, reduction of inflammation and allergy, and modulation of MITF function.

Clinical and Biological Characterization of Skin Pigmentation Diversity and Its Consequences on UV Impact

Skin color diversity is the most variable and noticeable phenotypic trait in humans resulting from constitutive pigmentation variability. This paper will review the characterization of skin pigmentation diversity with a focus on the most recent data on the genetic basis of skin pigmentation, and the various methodologies for skin color assessment. Then, melanocyte activity and amount, type and distribution of melanins, which are the main drivers for skin pigmentation, are described. Paracrine regulators of melanocyte microenvironment are also discussed. Skin response to sun exposure is also highly dependent on color diversity. Thus, sensitivity to solar wavelengths is examined in terms of acute effects such as sunburn/erythema or induced-pigmentation but also long-term consequences such as skin cancers, photoageing and pigmentary disorders. More pronounced sun-sensitivity in lighter or darker skin types depending on the detrimental effects and involved wavelengths is reviewed.

Postinflammatory Hyperpigmentation: Epidemiology, Clinical Presentation, Pathogenesis and Treatment

Postinflammatory hyperpigmentation (PIH) is a reactive hypermelanosis that develops following cutaneous inflammation. Common causes of PIH include intrinsic skin conditions (e.g., acne and eczema) as well as external insults to the skin, such as burn injuries and dermatologic procedures. PIH more commonly occurs in individuals with darker skin, for whom it is often a source of significant psychological distress. Several therapeutic modalities are available for the treatment of PIH, including topical agents, chemical peels, and energy-based devices. We review the epidemiology, clinical presentation, pathogenesis, and treatment of PIH.

Q-switched double frequency Nd:YAG 532-nm nanosecond laser vs. double frequency Nd:YAG 532-nm picosecond laser for the treatment of solar lentigines in Asians

Solar lentigines are common pigmentary lesions. Q-switched lasers are effective treatment options but postinflammatory hyperpigmentation (PIH) is common in darker skin. The objective of the study is to compare the efficacy and safety in solar lentigines of Asian skin treated by Q-switched potassium titanyl phosphate (KTP) 532-nm nanosecond laser vs. KTP 532-nm picosecond laser for the treatment of solar lentigines in Asians. Thirty patients with at least 2 solar lentigines on the upper extremities were enrolled. A total of 30 paired lentiginous lesions were randomly treated with a single treatment of either Q-switched KTP 532-nm nanosecond laser vs. KTP 532-nm picosecond laser. In terms of efficacy, mean luminance score was evaluated at baseline, at 6th, and 12th week. Degree of pigment clearance was assessed by a blinded physician and the patients. Satisfaction score was rated by patients using visual analogue scale. Adverse events were also recorded. Twenty-eight patients completed the study. Both lasers showed significant improvement in mean luminance score from baseline (p < 0.05). Likewise, there was no significant difference in pigment clearance between two lasers either assessed by physician or patients. However, patients' satisfaction score was significantly higher with the picosecond laser (p = 0.014). Adverse events and pain were not different between groups. Q-switched KTP 532-nm nanosecond laser and KTP 532-nm picosecond laser are safe and effective for treating solar lentigines in Asians. Based on cost-effectiveness, Q-switched KTP 532-nm nanosecond laser remains the main treatment while KTP 532-nm picosecond laser can be considered as a treatment option.

Postinflammatory hyperpigmentation: A comprehensive overview: Treatment options and prevention

Postinflammatory hyperpigmentation (PIH) occurs after various dermatoses, exogenous stimuli, and dermatologic procedures. The clinical course of PIH is chronic and unpredictable, although the probability of resolution of epidermal hyperpigmentation is better than those of dermal hyperpigmentation. PIH can be prevented or alleviated. When it does occur, the underlying inflammatory conditions should be sought and treated as the first step to reduce the progression of inflammation and PIH (which is an inflammatory consequence). If the inflammatory conditions subsides or there is no evidence of inflammation at the time of diagnosis, the treatments of PIH should be considered as the next step. Understanding the available treatment options helps the physician choose the appropriate treatment for each patient. Having a reproducible model for PIH is essential for the development of treatment modalities. The second article in this 2-part continuing medical education series on PIH specifically addresses the evidence that supports medical and procedural treatments of PIH and other forms of acquired hyperpigmentation. It also describes a PIH model and provides an algorithm for clinical practice along with discussion about the prevention of PIH.

Postinflammatory hyperpigmentation associated with treatment of solar lentigines using a Q-Switched 532-nm Nd: YAG laser: a multicenter survey

PURPOSE

To characterize the risk factors of Korean patients for postinflammatory hyperpigmentation (PIH) during treatment of solar lentigines using a Q-switched 532-nm Nd: YAG (QS 532 NY) laser.

MATERIALS AND METHODS

The present retrospective multicenter study was conducted at the dermatology clinics of five tertiary hospitals in Korea. Between October 2007 and January 2013, 516 patients were enrolled and reviewed for clinical features and factors associated with PIH.

RESULTS

The overall incidence of PIH was 20.3%. We demonstrated that patients with erythematous lentigines presented with PIH more frequently compared with those without erythematous lentigines. Among several coexisting conditions, facial diffuse dyschromia was significantly associated with PIH. Furthermore, PIH occurred more frequently in patients with invisible pores and velvety skin. However, age, sex, Fitzpatrick skin's phototype and season of treatment showed little association with PIH.

CONCLUSIONS

When a QS 532 NY laser is used to treat individuals with erythematous lentigines, invisible pores and velvety skin, and facial diffuse dyschromia, clinicians should be cautious and consider preventive measures.

Q-Switched 660-nm Versus 532-nm Nd: YAG Laser for the Treatment for Facial Lentigines in Asian Patients: A Prospective, Randomized, Double-Blinded, Split-Face Comparison Pilot Study

BACKGROUND

Q-switched (QS) 532-nm lasers are widely used to treat solar lentigines.

OBJECTIVE

To compare the efficacy and safety of 660-nm and 532-nm QS neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers in the treatment for lentigines in Asians.

MATERIALS AND METHODS

The halves of each face (randomly chosen) of 8 Korean Fitzpatrick Skin Type III-IV women with facial solar lentigines were treated with either 660-nm or 532-nm lasers. Pigmentation was measured objectively using a profilometric skin analysis tool and subjectively using the pigmentation area and severity index (PSI) score, global assessment of the aesthetic improvement scale (GAIS), and a patient satisfaction score at Weeks 4 and 8.

RESULTS

Seven patients completed the study. No significant differences were found in the PSI, GAIS, patient satisfaction score, and melanin average score between the lasers. The melanin average level was significantly reduced by the 660-nm laser but not the 532-nm laser at Week 8 compared with the baseline.

CONCLUSION

Both 660-nm and 532-nm QS Nd:YAG lasers effectively reduce pigmentation for up to 8 weeks with high patient satisfaction. The new 660-nm laser therefore increases the treatment options for lentigines in Asian skin.

The use of sunscreen starting on the first day after ablative fractional skin resurfacing

BACKGROUND

The most common side-effect of ablative fractional skin resurfacing in Asians is post inflammatory hyperpigmentation (PIH). Various attempts have been made to reduce the occurrence of PIH after laser treatment including sun avoidance, the use of preoperative and postoperative treatment regimens, and treatment using conservative energy settings and epidermal protection.

OBJECTIVES

To determine whether the use of broad-spectrum sunscreen with anti-inflammatory agents starting on the first day after fractional CO2 laser skin resurfacing reduces the incidence of post laser PIH.

MATERIALS AND METHODS

Thirty patients were treated with ablative fractional CO2 resurfacing on both sides of their faces at 10 mJ and 10% density. Each subject was randomly treated on one side of the face with petrolatum ointment four times a day for the first week after laser treatment and on the other side of the face with petrolatum ointment four times a day plus broad-spectrum sunscreen with anti-inflammatory agents in the morning starting on the first day after laser treatment. Transepidermal water loss was recorded at baseline and every day for 1 week. Melanin and erythema indexes were measured at baseline, 1-, 2-week, 1-, 2- and at 3-month post treatment.

RESULTS

Of the 30 patients involved in the study, 26 received the treatment and attended 1-, 2-week, 1-, 2- and 3-month post-treatment visits. Four patients were withdrawn from the study because they could not attend every follow-up visit. There was no statistically significant difference in transepidermal water loss at baseline, immediately after laser treatment, or at the D1 to D7 follow-up visits. Erythema index had no significantly statistical difference at baseline, 1-, 2- and at 3-month after laser treatment. Furthermore, there was a statistically significant difference in melanin index at 1-week post laser treatment between both sides (P = 0.001). Melanin index at the 1-week follow-up visit on the side treated with broad-spectrum sunscreen with anti-inflammatory agents starting on the first day after laser treatment was significantly less than the control side.

CONCLUSION

The use of broad-spectrum sunscreen with anti-inflammatory agents starting on the first day after ablative fractional skin resurfacing can decrease the incidence of PIH after laser treatment at 1-week postoperatively.