Introduction
Vitiligo is an acquired autoimmune disease involving
the loss of melanocytes as the main characteristic feature,
resulting in colorless patches (1,2). It
affects 0.5-2% of the population among adults and children
worldwide (2). Although some
guidelines for the treatment of vitiligo have been released
(3,4), the treatment of vitiligo remains a
difficult challenge in dermatology. There are various treatments
available, such as surgery, topical and systemic
immunosuppressants, make-up and phototherapy (3-6).
Phototherapy, the main method used for the treatment
of vitiligo, has various efficacies. Among these, narrow-band
ultraviolet B (NB-UVB) and ultraviolet A (UVA) have been used for
decades with good efficacy. NB-UVB is one of the main treatments
used for vitiligo. Due to its efficacy and minimal side-effects, it
has become the mainstay for the widespread treatment of vitiligo
(7). The Vitiligo Working Group
(VWG) recommended that the use of NB-UVB two or three times per
week is an optimal weekly frequency for the treatment of vitiligo)
(7).
Monochromatic excimer light (MEL, 308 nm) was
developed for use in dermatology (8), and has become the mainstay treatment
for vitiligo due to its good efficacy and limited side-effects. The
specification of the UV light therapy instrument used in this
experiment is: Dema XECL-308. Despite its widespread use, there are
almost no standardized guidelines available on the dose and
frequency of MEL application for the treatment of vitiligo.
Therefore, the present study aimed to examine the
different efficacy of the use of different frequencies of MEL
administration in a larger number of patients with vitiligo.
Patients and methods
Study approval and design
The research program was confirmed by the Medical
Ethics Committee of the Affiliated Hospital of Jining Medical
University (Jining, China; ethical approval no. 2022C261). The
study was performed at the Dermatology Department of the Affiliated
Hospital of Jining Medical University. Informed consent was
obtained from all the patients and/or their guardians.
A total of 296 subjects were divided into five
sub-samples according to the different areas of phototherapy: Neck,
face, trunk, extremities and scalp. The present study was designed
as a cross-sectional study. The median age of the patients was 15
years, with a maximum age of 70 years and a minimum age of 2.2
years. The patients were then subdivided into five sub-samples by
site. A Chi-squared test, rank sum test and a two independent
samples t-test were used to confirm whether the frequency of
phototherapy yielded a difference in the frequency of the treatment
or the number of initial color restorations. There was no
difference in the former, leading to conclusion 1: It cannot yet be
assumed that there is a difference in the treatment efficacy
between phototherapy performed once or twice-weekly, and that
phototherapy performed once weekly is effective; there was no
difference in the latter, leading to conclusion 2: It cannot yet be
assumed that there is a difference between phototherapy performed
weekly and twice weekly in terms of the number of initial color
restorations, so that with the same number of color restorations,
weekly phototherapy requires a longer treatment duration than
phototherapy performed twice weekly.
Patients
Patients were recruited from the outpatient clinic
of the Department of Dermatology at the Affiliated Hospital of
Jining Medical College for a period of 2 years and 3 months, i.e.,
between June, 2018 and September, 2020. Patients with non-segmental
vitiligo were included in the present study. Adult patients with
symmetrical vitiligo with lesions of at least 10 cm2 and
at least 3 months of age were included in the study. The exclusion
criteria were topical or systemic treatment 4 weeks prior to the
study, phototherapy 12 weeks prior to the study, previous skin
cancer or radiotherapy at the treatment site, pregnancy and other
contraindications to phototherapy (9).
Statistical analysis
In the present study, IBM SPSS Statistics 26
software was used to analyze the data. Data were analyzed using a
Chi-squared test, as well as a one-sample rank sum test and a two
independent samples t-test. A value of P<0.05 was considered to
indicate a statistically significant difference.
Results
Between June, 2018 and September, 2020, a total of
296 patients with a clinical diagnosis of non-segmental vitiligo
were included in the present study. The characteristics of the
patients including sex, age, medical history (duration of
vitiligo), number of treatments until repigmentation was achieved,
the dose at which color was restored, the area of the body and
effects under different treatment frequencies are presented in
Table I.
 | Table IBasic information of the patients with
vitiligo treated with phototherapy once vs. twice a week. |
Table I
Basic information of the patients with
vitiligo treated with phototherapy once vs. twice a week.
| No. of light
treatments | Sex (no. of
patients) | Age (years) | Medical history
(duration of vitiligo; months) | No. of treatments
until repigmentation was achieved | Number of doses
required to achieve recoloration | Affected body part
(no. of patients) | Effects of treatment
(no. of patients) |
|---|
| Once a week | Male (79) | 18.69±12.24 | 9.00±13.02 | 4.94±3.51 | 7.31±6.87 | Face (66) | Healing (45) |
| | Female (84) | | | | | Neck (17) | Effective (117) |
| | | | | | | Torso (44) | Invalid (1) |
| | | | | | | Extremities (28) | |
| | | | | | | Scalp (8) | |
| Twice a week | Male (73) | 20.71±14.36 | 6.55±10.08 | 5.15±3.57 | 7.82±7.95 | Face (55) | Healing (33) |
| | Female (60) | | | | | Neck (16) | Effective (98) |
| | | | | | | Torso (25) | Invalid (2) |
| | | | | | | Extremities (27) | |
| | | | | | | Scalp (10) | |
In Table II,
‘healing’ indicates that the skin lesions of patients with vitiligo
had completely returned to normal following treatment; ‘effective’
indicates that the skin lesions of patients with vitiligo notably
improved following treatment, but had not recovered completely;
‘invalid’ indicates that the skin lesions of patients with vitiligo
remained almost unaltered following treatment; and ‘total’
represents the total number of patients with vitiligo. In Table II, the Chi-squared test was used to
determine difference in efficacy between phototherapy performed
once and twice weekly. As shown by the results, that the difference
in the efficacy of the frequency of phototherapy in the five
regions of the face, neck, trunk, extremities and scalp was not
statistically significant. Thus, it cannot yet be assumed that
there is a difference in the therapeutic efficacy between
phototherapy performed once or twice weekly.
| Table IIComparison of the efficacy of
different phototherapy sessions for patients with vitiligo treated
with phototherapy in the present study. |
Table II
Comparison of the efficacy of
different phototherapy sessions for patients with vitiligo treated
with phototherapy in the present study.
| Affected body
part | No. of light
treatments per week | Healing (no. of
patients) | Effective (no. of
patients) | Invalid (no. of
patients) | Total (no. of
patients) | P-value |
|---|
| Face | 1 | 25 | 41 | 0 | 66 | 0.354 |
| | 2 | 19 | 36 | 0 | 55 | |
| Neck | 1 | 3 | 13 | 1 | 17 | 0.971 |
| | 2 | 3 | 13 | 0 | 16 | |
| Torso | 1 | 10 | 34 | 0 | 44 | 0.070 |
| | 2 | 5 | 20 | 0 | 25 | |
| Extremities | 1 | 5 | 23 | 0 | 28 | 2.185 |
| | 2 | 4 | 21 | 2 | 27 | |
| Scalp | 1 | 2 | 6 | 0 | 8 | 0.064 |
| | 2 | 2 | 8 | 0 | 10 | |
| Total | | 78 | 215 | 3 | 296 | |
The present study then examined whether there was a
difference in the number of treatments to achieve recoloration with
different phototherapy frequencies. As shown in Table III, the one-sample rank sum test
was used for the male, female, face, neck, trunk and scalp samples
as they did not meet normality, and two independent samples t-tests
were used for extremity samples which met normality, all with
P-values >0.05, indicating no statistically significant
differences. Thus, it cannot yet be assumed that there is a
difference in the number of phototherapy sessions performed once
vs. twice weekly as regards the restoration of color. With the same
number of times, phototherapy performed once weekly requires a
longer treatment duration than phototherapy performed twice
weekly.
| Table IIIDifference in the number of treatments
when reaching recoloration for patients with vitiligo treated with
different frequencies of phototherapy. |
Table III
Difference in the number of treatments
when reaching recoloration for patients with vitiligo treated with
different frequencies of phototherapy.
| | Male | Female | Face | Neck | Trunk | Extremities | Scalp |
|---|
| Treatment times per
week | 1 | 2 | 1 | 2 | 1 | 2 | 1 | 2 | 1 | 2 | 1 | 2 | 1 | 2 |
|---|
| No. of treatments
until repigmentation was achieved (mean ± SD) | 4.99±3.24 | 5.49±3.259 | 4.90±3.76 | 4.73±3.912 | 3.68±1.824 | 3.80±1.976 | 4.47±2.095 | 5.19±3.124 | 4.05±2.134 | 4.88±3.887 | 9.11±5.343 | 8.16±4.661 | 6.75±3.454 | 5.60±3.134 |
| | 5.23±3.248 | 4.83±3.811 | 3.74±1.888 | 4.82±2.627 | 4.35±2.894 | 8.66±5.007 | 6.11±3.234 |
| P-value | 0.217 | 0.600 | 0.802 | 0.709 | 0.445 | 0.318 | 0.360 |
Discussion
Research has indicated that following 308 nm excimer
laser treatment, the number and volume of melanocytes in vitiligo
lesions are increased compared to previous ones, and the migration,
activation and production of melanin induces pigmentation on the
skin surface (10). Compared to
NB-UVB phototherapy (311-313 nm), 308 nm excimer laser appears to
augment and expedite the repigmentation process (11,12). In
addition, the 308 nm excimer laser enhances and accelerates the
pigmentation process to a greater extent than NB-UVB phototherapy
(13), which not only provides more
rapid results and shorter treatment durations, but also limits the
accumulation of UV radiation, and may thus reduce the risk of
developing skin cancer (14-17).
The 308 nm excimer light is currently replacing NB-UVB as a more
effective treatment for vitiligo. It has been reported that there
is no necessary link between the course of vitiligo and disease
progression and treatment outcomes (18). Therefore, the present study did not
consider the duration of the disease and treatment progression, but
used a cross-sectional approach, focusing on the frequency of
treatment. The current optimal treatment regimen for vitiligo is
three weekly phototherapy sessions (7); however, it has been found that a once
weekly session of phototherapy is also effective. The Consensus on
the Treatment of Vitiligo (2021 Edition) also recognizes the
effectiveness of weekly phototherapy (19), and the optimal frequency of excimer
light therapy remains to be investigated. It has been demonstrated
that the final repigmentation results of the 308-nm excimer laser
are not associated with the frequency of treatment (20). This provides strong evidence to
support the findings of the present study. In addition, numerous
patients in remote areas are unable to complete phototherapy twice
or thrice weekly, and it is thus critical to explore the
effectiveness of weekly phototherapy. Therefore, the present study
examined whether there was any difference between light therapy
performed once and twice weekly in terms of treatment efficacy and
the number of initial color restorations to determine whether light
therapy performed twice weekly is more effective. The results
revealed that there was no significant difference between
phototherapy performed once or twice weekly in terms of treatment
efficacy and the number of initial color restorations. Weekly light
therapy was effective; however, for the same number of treatments,
weekly light therapy took longer than light therapy performed twice
weekly to restore color for the first time.
The study population examined herein was selected
from patients who visited the outpatient clinic during a total of 2
years and 3 months from June, 2018 to September, 2020. The
limitations of the present study are the use of cross-sectional
surveys, too wide an age span and the lack of follow-up, which may
lead to survey bias. A larger sample data and a homogeneous
population need to be selected in the future to validate the
results obtained herein. In addition, the number of patients with
vitiligo in the neck and scalp areas was minimal in the study
sample and the results may thus be subject to error.
In conclusion, the present study demonstrated that
the difference in efficacy between phototherapy performed twice or
once weekly was not significant. Although weekly light therapy is
effective, it requires a longer duration to be effective compared
with light therapy performed twice weekly.
Acknowledgements
Not applicable.
Funding
Funding: Funding for the present study was provided by the
Shandong Province TCM Science and Technology Program (grant no.
M-2022249).
Availability of data and materials
The datasets used and/or analyzed during the current
study are available from the corresponding author on reasonable
request.
Authors' contributions
All authors (JYW, SLY, XYH, HLX and BL) contributed
to the results of the study and accept public responsibility for
the corresponding parts of the study. All authors agree to take
responsibility for all aspects of the study to ensure the accuracy
and completeness of this thesis. JYW and BL were responsible for
the experimental design, searched the literature and wrote the
manuscript. SLY collected the data. XYH and HLX analyzed the data.
JYW and BL confirm the authenticity of all the raw data. All
authors have read and approved the final manuscript.
Ethics approval and consent to
participate
The present study was reviewed by the Medical Ethics
Committee of the Affiliated Hospital of Jining Medical University
(Jining, China; approval no. 2022C261). Informed consent was
obtained from all the patients and/or their guardians after the
possible side-effects of the treatment protocol were explained.
Patient consent for publication
Not applicable.
Competing interests
The authors declare that they no competing
interests.
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