To the Editor: Laser resurfacing has been difficult historically in people with darker skin tones given the increased risks of adverse events (AEs). Available treatments may incite further pigment alteration and scarring. Nonablative fractionated resurfacing, such as 1540/1550-nm technology, is used for a myriad of treatments, including rejuvenation, dyschromia, scar reduction, and blemish removal.1 Early findings show favorable outcomes in people with Fitzpatrick skin types (FSTs) IV to VI.2,3 The purpose of this study was to further evaluate and characterize the efficacy and safety profile of nonablative fractional 1540-nm laser treatment in patients with darker skin tones.
A 10-year, single-center, retrospective analysis of adults who received at least 1 treatment with the nonablative fractional 1540-nm laser was conducted to determine the frequency of AEs in patients with FSTs I to VI. AEs are reported standardly in chart notes at this institution. All treatments were performed by board-certified dermatologists with extensive laser training and experience. A total of 1160 patients were treated with the 1540-nm modality during the study period. The average treatment had 277 pulses, had a pulse duration of 14.88 seconds, and required 2.9 passes to complete. Of the 1160 treatments included in the analysis, 140 (12.07%) were associated with an AE (Table I). The most frequently reported AEs were extended redness (91, 7.84%), swelling (28, 2.41%), and crusting (17, 1.47%), with the majority occurring on the face (130, 11.21%) (Table II). The most common indications for all treatments were scar (81.56%), dyschromia (8.10%), and striae (5.86%). Of these treatments, scar treatment was associated with the highest rate of total AEs (13.31%). Patients aged from 35 to 44 years (19.00%) and 45 to 54 years (16.96%) had the highest percentage of AEs. Furthermore, there was a statistically significant difference in the mean pulse count between those who experienced AEs (mean pulse count, 240.86) and those who did not (mean pulse count, 182.16; P = .0010). The majority of patients (69.13%) considered their treatment helpful and reported an improvement in their condition.
Table I.
Demographic information
| Population characteristics | Total cohort (%), n = 1160 | No adverse events (%), n = 1015 | Adverse events (%), n = 140 | Not reported | ||
|---|---|---|---|---|---|---|
| Race | ||||||
| American Indian | 41 (3.53) | 34 (82.93) | 7 (17.07) | 0 | ||
| Asian | 189 (16.29) | 176 (93.12) | 13 (6.88) | 0 | Race | P value |
| Black/African American | 117 (10.09) | 111 (94.87) | 4 (3.42) | 2 | White vs Black | .0024† |
| Hispanic or Latino | 103 (8.8) | 77 (74.76) | 26 (25.24) | 0 | White vs Asian | .0276∗ |
| Middle Eastern | 29 (2.50) | 29 (100.00) | 0 (0.00) | 0 | White vs Hispanic | .0036† |
| Other, Pacific Islander | 4 (0.34) | 4 (100.00) | 0 (0.00) | 0 | Black vs Asian | .3041 |
| Other | 20 (1.72) | 18 (90.00) | 2 (10.00) | 0 | Black vs Hispanic | <.0001‡ |
| White | 454 (39.14) | 393 (86.56) | 59 (13.00) | 2 | Asian vs Hispanic | <.0001‡ |
| Declined | 203 (17.50) | 173 (85.22) | 29 (14.29) | 1 | ||
| Gender | ||||||
| Male | 406 (35.00) | 376 (92.61) | 30 (7.39) | 0 | ||
| Female | 754 (65.00) | 639 (84.75) | 110 (14.59) | 5 | ||
| FST | ||||||
| I | 5 (0.43) | 2 (40.00) | 3 (60.00) | 0 | ||
| II | 303 (26.12) | 264 (87.13) | 37 (12.21) | 2 | ||
| III | 203 (17.50) | 185 (91.13) | 18 (8.87) | 0 | ||
| IV | 174 (15.00) | 146 (83.91) | 28 (16.09) | 0 | ||
| V | 97 (8.36) | 87 (89.69) | 9 (9.28) | 1 | ||
| VI | 28 (2.41) | 26 (92.86) | 2 (7.14) | 0 | ||
| Not applicable | 350 (30.17) | 305 (87.14) | 43 (12.29) | 2 |
All analyses were conducted using Prism 9 GraphPad Software via Fischer’s exact test.
P < .05
P < .01
P < .001.
Table II.
Adverse event characteristics
| Location of AEs | AE present | AE absent | Unknown status AE | % of total reported AEs | ||||
|---|---|---|---|---|---|---|---|---|
| Face | 130 | 816 | 5 | 13.67% | ||||
| Trunk | 2 | 68 | 0 | 2.94% | ||||
| Extremities | 7 | 81 | 0 | 8.64% | ||||
| Most common AEs | Total count | FSTs I and II | FSTs III and IV | FSTs V and VI | Unknown FST | AE absent | Unknown | % of specific indication |
| Redness | 91 | 33 | 24 | 8 | 26 | 73 | 0 | 5.19% |
| Swelling | 28 | 9 | 15 | 0 | 4 | 801 | 5 | 13.52% |
| Crusting | 17 | 5 | 9 | 1 | 2 | 61 | 0 | 8.96% |
| Hyperpigmentation | 13 | - | - | - | - | |||
| Acne | 13 | - | - | - | - | |||
| Scabbing | 8 | - | - | - | - | |||
| Indications for treatment | AE present | Laser settings | Mean pulse count | Mean pulse duration | ||||
| Dyschromia | 4 | AE present | 240.86 | 15.00 | ||||
| Scar | 126 | AE absent | 182.16 | 14.87 | ||||
| Striae | 6 |
Black (3.42% Black vs 13.00% White; P = .0024), Asian (6.88% Asian vs 13.00% White; P = .0276), and Hispanic (25.24% Hispanic vs 13.00% White; P = .0036) patients had statistically significantly different rates of AEs compared with White patients based on the assessment by Fisher’s exact test. Differences in the rates of AEs may be related to higher energy used in patients with FSTs I to III, provider-dependent differences, prior retinol use, and/or use of overall more conservative parameters (ie, lower pulse count and less overlap) in some groups.
The strength of this study is the diversity of patients, both in terms of FST and race/ethnicity. The limitation lies in the single-center design, which may limit generalizability. We hope to add to the body of literature that can provide evidence-based support for protocol determination, patient education, and continued training and research on cosmetic treatments in patients with darker skin tones. In dermatologists with trained expertise, the 1540-nm nonablative fractional laser treatment is an effective and safe method for improving scar, dyschromia, and striae in all skin types.
Conflicts of interest
None disclosed.
Footnotes
Funding sources: None.
Patient consent: Not applicable.
IRB approval status: Reviewed and approved by Boston Medical Center, approval H-42427.
References
- 1.Hedelund L., Moreau K.E., Beyer D.M., Nymann P., Haedersdal M. Fractional nonablative 1,540-nm laser resurfacing of atrophic acne scars. A randomized controlled trial with blinded response evaluation. Lasers Med Sci. 2010;25(5):749–754. doi: 10.1007/s10103-010-0801-1. [DOI] [PubMed] [Google Scholar]
- 2.Yoo K.H., Ahn J.Y., Kim J.Y., Li K., Seo S.J., Hong C.K. The use of 1540 nm fractional photothermolysis for the treatment of acne scars in Asian skin: a pilot study. Photodermatol Photoimmunol Photomed. 2009;25(3):138–142. doi: 10.1111/j.1600-0781.2009.00430.x. [DOI] [PubMed] [Google Scholar]
- 3.Kaushik S.B., Alexis A.F. Nonablative fractional laser resurfacing in skin of color: Evidence-based review. J Clin Aesthet Dermatol. 2017;10(6):51–67. [PMC free article] [PubMed] [Google Scholar]