Background and objectives: The reaction to intense pulsed light (IPL) on Asian skin often differs from that on Caucasian skin. The study reported herein evaluated the effect on acne vulgaris of IPL alone and when IPL was combined with photodynamic therapy (PDT) using topical methyl aminolevulinate (MAL) in Asians.
Study design/materials and methods: Thirty Chinese subjects with phototypes IV or V and moderate acne were enrolled for a randomized, half-facial treatment study with IPL alone, IPL with PDT, or as controls. Sixteen percent MAL cream was applied to half of the face 30 minutes before treatment in the PDT group. The IPL was provided by the Ellipse Flex system (Danish Dermatologic Development, Denmark), which emitted wavelengths of 530 to 750 nm. The subjects were treated four times at 3-week intervals. Single passes of double pulses with a 10 milliseconds delay and a pulse duration of 2.5 milliseconds were used. The assessment of inflammatory and non-inflammatory acne lesions by two blinded investigators was based on standardized photographs that were taken before each treatment, and at 4 and 12 weeks after the final treatment.
Results: Twenty-three patients completed the study. The mean reduction of the inflammatory lesion count was 53% in the PDT group, 22% in the IPL group, and 72% in the control group at 4 weeks, and 65% in the PDT group, 23% in the IPL group, and 88% in control group at 12 weeks. The mean clearance of non-inflammatory lesions was 52% in the PDT group, 15% in the IPL group, and 14% in the control group at 4 weeks, and 38% in the PDT group and 44% in the IPL group at 12 weeks, when and an increase of 15% was noted in the control group. Most patients experienced a reduction of inflammatory lesions that was not statistically significant on the PDT-treated side (P = 0.06) or the IPL-treated side (P = 0.82) at 12 weeks after treatment. Pretreatment with MAL resulted in a better clearance of inflammatory acne than IPL alone. There were no statistically significant differences between the intervention groups and the control group in the mean reduction of inflammatory lesions. Significant reductions of non-inflammatory lesions were observed in the MAL-PDT group (38%, P = 0.05) and IPL groups (43%, P = 0.00) 12 weeks after treatment. Twenty-five percent of the subjects in the PDT group withdrew because of intolerance to procedure-related discomfort.
Conclusions: MAL-PDT using IPL and MAL in Asians did not lead to significant improvement of moderate inflammatory acne compared with the control group. However, there was a delayed effect on non-inflammatory lesions, with significant reductions in both the PDT and IPL groups. A proportion of patients could not tolerate the discomfort that was related to PDT despite the short MAL incubation.
(c) 2006 Wiley-Liss, Inc.