Quantitative assessment of narrow-band UVB induced tanning during phototherapy in Korea
Narrow-band (TL-01) UVB lamps are being increasingly used for phototherapy of psoriasis and other dermatoses, for their excellent effect compared with broad-band UVB sources. Many patients receiving phototherapy have complained about the tanning effect of ultraviolet radiation especially in dark-skinned ones. So we wished to know the degree of pigmentation induced by phototherapy during narrow-band UVB treatment. Methods:
A total of 20 psoriasis patients receiving narrow-band UVB phototherapy were included in this study. A Minolta spectrophotometer CM-2002 was used to measure pigmentation. All patients were evaluated for skin color every seventh day for 7 weeks. The L* value (luminance) gives information about the relative lightness ranging from total black to pure white. The a* value represents the balance between red and green, and the b* value between yellow and blue. Results:
The L* values which indicate luminance decreased continuously until the 5th week, when maximum tanning was obtained. Afterwards minimal change was observed until the 7th week. The change of a* and b* values also showed the pattern that was compatible with the above results. The mean individual typology angle of our subjects was 41.9°, which indicated they fell into ‘light’ group of constitutional skin color category. Conclusion:
From this study, we found that pigmentation induced by narrow-band UVB phototherapy increased continuously until the 5th week and then did not progress. Our results provide standard data of skin pigmentation during narrow-band UVB phototherapy in Korean brown skin.
Document Type: Research Article
Affiliations: Department of Dermatology, Seoul National University College of Medicine and Clinical Research Institute, Seoul National University Hospital, Seoul, Korea
Publication date: 2002-06-01