Conflict of interest None of the authors have any conflicts of interest pertaining to commercial sources.
Comparative study of treatment efficacy and the incidence of post-inflammatory hyperpigmentation with different degrees of irradiation using two different quality-switched lasers for removing solar lentigines on Asian skin
Article first published online: 20 DEC 2011
© 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology
Journal of the European Academy of Dermatology and Venereology
Volume 27, Issue 3, pages 307–312, March 2013
How to Cite
Negishi, K., Akita, H., Tanaka, S., Yokoyama, Y., Wakamatsu, S. and Matsunaga, K. (2013), Comparative study of treatment efficacy and the incidence of post-inflammatory hyperpigmentation with different degrees of irradiation using two different quality-switched lasers for removing solar lentigines on Asian skin. Journal of the European Academy of Dermatology and Venereology, 27: 307–312. doi: 10.1111/j.1468-3083.2011.04385.x
Funding sources No funding was received for this study.
- Issue published online: 18 FEB 2013
- Article first published online: 20 DEC 2011
- Received: 17 July 2011; Accepted: 14 November 2011
Background Quality-switched (QS) lasers are well-known effective treatment for removing solar lentigines. However, the high incidence of post-inflammatory hyperpigmentation (PIH) raises concern in darker skin types. This is the first study comparing efficacies and incidences of PIH in Asian skin with different degrees of irradiation between two QS lasers.
Method In total, 355 solar lentigines in 193 cases, skin types III–V, were randomly divided into four groups. All cases received single laser treatment. Clinical results were evaluated after 4 weeks. Groups 1 and 3 were treated ‘aggressively’ with endpoints of very obvious immediate whitening (IW) of the lesion. Groups 2 and 4 were treated ‘mildly’ with endpoints of slight IW of the lesion. Groups 1 and 2 were irradiated with the QS ruby, and groups 3 and 4 with the QS frequency doubled Nd:YAG laser.
Results There were no statistically significant differences in degrees of clearance among the four groups. However, PIH incidences were very different: 33.33%, 7.47%, 23.18% and 8.47% in groups 1, 2, 3 and 4 respectively. The difference between aggressively and mildly irradiated groups (1 and 3 vs. 2 and 4) was statistically significant (P < 0.001). However, there was no statistical difference between the two aggressively or the two mildly irradiated groups. There were no significant differences between skin types.
Conclusion Aggressive irradiation using QS lasers resulted in a high PIH incidence, while having no advantage in efficacy. For darker skin types, mild irradiation reduces the PIH risk with no disadvantage in efficacy.