The researchers note that although both treatments were beneficial, the effects obtained using PDL were more sustained than those produced using IPL.
“Despite the well-known effectiveness of laser-based methods, debate continues on the relative advantages of PDL and IPL treatments for acne and on the modes of action involved in their clinical efficacy,” say Dae Hun Suh (Seoul National University College of Medicine, Korea) and team.
“Moreover, the basic question concerning the relative effectiveness of these two modalities remains unanswered,” they add.
The researchers treated 20 patients with facial acne with PDL on one side of the face and IPL on the other to compare efficacy and safety of the two treatments. In total the patients were treated four times with each treatment at 2-week intervals.
The effectiveness of the treatments was assessed by comparing lesion count, acne severity, patient subjective self-assessments of improvement, and histopathological examinations.
Writing in the Journal of the European Academy of Dermatology and Venereology, the authors report that the number of acne lesions decreased with both treatments and there was no significant difference in degree of improvement between them.
IPL treatment was initially quicker acting and had a more significant effect than PDL. But, by 8 weeks after the last treatment acne had started to rebound on the IPL-treated sides, but not the PDL-treated sides.
The histopathological assessment showed a reduced inflammatory reaction and an increase in transforming growth factor-β after both treatments, but this was more pronounced in the PDL-treated sides.
“In summary, both IPL and PDL treatments were found to be effective and safe for acne,” conclude the investigators.
“However, whether any other type of non-ablative laser that can induce a photothermal reaction could be used as an effective modality for the treatment of acne remains unanswered.”
