In vivo microscopic approaches for facial melanocytic lesions after quality-switched ruby laser therapy: time-sequential imaging of melanin and melanocytes of solar lentigo in Asian skin

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.

Efficacy of D-pigment dermocosmetic lightening product for solar lentigo lesions of the hand: A randomized controlled trial

Solar lentigo, benign lesions which mostly appear on chronically, sun-exposed surfaces, are associated with ageing. Patients are increasingly requesting a more uniform skin texture, especially for hands. Treatment options include dermoabrasion, intense pulsed light, cryotherapy, peelings, and laser therapy. Topical compounds can be employed, in alternative or associated with dermatologic procedures. The current study was designed to evaluate solar lentigo hyperpigmentation, skin architecture and clinician and patient assessments comparing a dermocosmetic lightening product (active) with a moisturizing product (control) according to clinical, digital and subjective analyses in 72 lesions over 12-month follow up period. Statistically significant differences were observed between the lesions treated with the active compared to the control in terms of papillary brightness (p = 0.03) and contrast (p = 0.03), and in the limitation of dermal-epidermal junction destructuring (p = 0.03) according to dermal-epidermal junction destructuring score at Reflectance Confocal Microscopy. Luminance (p = 0.04) and redness (p = 0.03) were improved at color analysis, and physician and patient evaluations favored the active in efficacy and patient satisfaction investigations. The dermocosmetic lightening product utilized in the current study proved to be more effective, according to clinical, digital and subjective analyses in reducing lesion hyperpigmentation, stabilizing the lesion skin architecture and increasing patient satisfaction compared to the control in a cohort of 36 subjects, over a 12-month period. Beside demonstrating the efficacy of this topical lightening product, we propose a “destructuring score”, which improves the robustness of solar lentigo’s evaluation, and can be used in future studies to standardize the quantitative comparisons of different treatment options.

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.

In vivo time-sequential histological study focused on melanocytes: suggestion of golden time for intervention to prevent post-laser pigmentary changes

BACKGROUND

Post-inflammatory pigmentary changes after laser treatments are challenging adverse effect.

OBJECTIVE

To suggest an ideal time period with regard to intervention to prevent post-laser pigmentary changes, an in vivo time-sequential histological study focused on melanocytes was performed.

METHODS

The back skin of four volunteers was irradiated with Q-switched alexandrite laser (QSAL). In one subject (subject 4), topical corticosteroid was applied onto the irradiated skin from the time of irradiation to day 28. In all subjects, time-sequential skin biopsies were performed at baseline, an immediate time after irradiation, day 2, day 7, and day 28. Histological and immunohistochemical analyses were conducted.

RESULTS

Q-switched alexandrite laser led to the successful removal of pigments and most melanocytes from the epidermis in all subjects. At day 28, there was increased epidermal pigmentation in the skin of the subjects 1-3. It was noted that numerous activated melanocytes appeared on day 7, continued to be observed until day 28. However, in the subject 4, the melanocyte activation and post-laser pigmentary changes were not observed.

CONCLUSION

In regard to intervene melanocyte activation, at least 1 week after laser treatment is suggested as a 'golden' time period to prevent pigmentary changes.