Dermoscopic changes in melanocytic nevi covered with both opaque tape and sunscreen cream during narrowband ultraviolet B therapy

Background Ultraviolet (UV) light may cause dermoscopic changes on melanocytic nevi (MN). Objectives To investigate the effects of sunscreen cream (SSc) application on dermoscopic changes in MN during narrowband UVB (NBUVB) therapy. Methods Half of the randomly selected MN in each patient were covered with opaque tape and SSc [SSc(+)], and the rest were covered with only opaque tape [SSc(−)] during NBUVB treatment sessions. Results More SSc(−) MN displayed dermoscopic changes at end of NBUVB therapy compared to the start of therapy (p=0.035). The number of the MN that decreased in size and showed loss of structure was significantly higher in SSc(−) MN (p=0.04 and p=0.026, respectively). Conclusions Sunscreen in combination with opaque tape may contribute to some dermoscopic changes in melanocytic nevi, including decrease in size and loss of structure.

opaque tape-without SSc application SSc(-). SSc was applied approximately 20 minutes before the opaque tape was applied. SPF 50 + SSc containing organic and inorganic filters against UVA-UVB (Solante; Buergli Pharma, Inc., Makati, Philippines) was used. Dermoscopic images of the selected MN were captured with a digital dermoscopy system at the beginning, at the end, and 3-6 months after the end of NBUVB therapy. At all follow-ups, total body mole mapping was performed with a fully automated body mole-mapping programme (Body Studio ATBM; FotoFinder Systems Inc, Columbia, MD, USA). Dermoscopic photographing, total body mole mapping, and arrangement of photographs were performed by one researcher (DÖK). The evaluation of the images was done by another researcher (NK) without knowing whether the lesion was SSc(+) or SSc(-). The MN that showed unexpected dermoscopic findings, such as decrease in size or loss of structure, were further evaluated by another researcher (IKK).
The data were analyzed with the SPSS Statistics 21 packet programme. Sustained variables were given as average ± standard deviation, minimum -maximum assets and categorical variables for numbers and percentages. In order to compare the independent group discrepancies, the Mann-Whitney U test was used. The differences between categoric variables were examined with Chi-square test. For examination of risk factors, the logistic regression test was used.

Results
Of the 24 patients enrolled, a total of 165 MN were identified.
Excluded from the study were 6 patients with 34 MN, who were lost to follow-up and 11 MN [3][4][5]. The dermoscopic changes observed in MN after NBUVB or ultraviolet A1 (UVA1) exposure did not occur in MN covered with opaque tape or sunscreen cream (SSc). In the direction of these findings, it was suggested that the dermoscopic changes induced by UVA1 and ultraviolet B (UVB) can be prevented successfully with either opaque tape or highly protective factor SSc; however, no significant histologic and immunohistochemical changes were detected in MN showing dermoscopic changes [6]. Although dermoscopic changes were recorded in a significantly few amount of covered MN during phototherapy sessions, they still occured in a noteworthy part of the covered MN [5,7,9]. The Turkish Dermatology Society Phototherapy Guidelines advise covering big and atypical MN and premalignant lesions before phototherapy [9].

Materials and Methods
All patients with a variety of dermatologic diseases were refered to our phototherapy unit for NBUVB therapy between January 28, 2015 and July 25, 2016 were evaluated in terms of eligibility for the study. The patients who were older than 1 year old and had at least two MN >2 mm size located on body and/or proximal extremity without melanoma suspicion were invited to participate in the study. Exclusion criteria included personal or family history of melanoma or cutaneous malignant epithelial tumor, active infection, atypical mole syndrome, active or previous history of systemic inflammatory or neoplastic disease, immunosuppressive medication, phototherapy history, and artificial UV exposure. MN located on sun-exposed body parts such as the head, neck, and distal extremities were not taken into consideration.
Every study participant signed an Informed Consent  Table 2).
In our study, we detected size change in the 27.5% of MN, 84.8% of which showed decrease in size. The ratios of MN that showed size decrease and structure loss were statistically significantly higher in the SSc(-) group compared to the SSc(+) group. In addition, we also found the ratios of MN that showed fading in pigmentation network and in pigmentation were also higher in the SSc(-) group, although the difference did not reach a statistically significant level.
We excised one of the MN that showed size decrease, fading in pigmentation, and pigmentation network, but no other dermoscopic change, and we did not detect atypical histopathologicafindings. We thought that the above-mentioned dermoscopic findings might have emerged by induction of melanocyte apoptosis and blockage of melanin production from melanocytes by NBUVB [19,20]. According to our findings, it can be speculated that SSc application in combination with opaque tape may hinder the triggering effects of NBUVB over MN involution.
Hofmann-Wellenhof et al detected significant darkening in brown color and total irregularity generation in uncovered MN during UVB treatment but no significant dermoscopic changes in those covered by opaque tape. However, when considering MN covered and uncovered with opaque tape together, they recognized that MN showed significantly more "total irregularity," darker "brown color," and increase in brown globules and pigment network width at the end of UVB treatment compared to the beginning. In all, they thought these changes may depend on the systemic effects of UV radiation on MN [5]. showing size decrease was for continued size reduction [16].
The majority of dermoscopic changes occured in our study showed a tendency to return to their former state at approximately a mean of 4.2 months after cessation of