Photodynamic Therapy for Acne: Not Always Effective

Summary and Comment |
April 6, 2007

Photodynamic Therapy for Acne: Not Always Effective

  1. George J. Hruza, MD

Once again, the inflammatory acne lesions did not respond to intense pulsed light either alone or with photodynamic therapy.

  1. George J. Hruza, MD

Intense pulsed light (IPL), alone or combined with topical photodynamic therapy, has shown promise for treating acne, but controlled studies have been very limited. In this randomized, prospective, blinded, split-face clinical trial from Hong Kong, 30 Asian patients were enrolled to study the effects on acne of IPL alone and combined with photodynamic therapy using topical methylaminolevulinate (MAL). Patients were randomized to treatment of one half the face with either 16% MAL plus IPL, IPL alone, or placebo, in a ratio of 1:2:1. At baseline, patients had at least 10 inflammatory lesions and had been off all acne medications for 2 weeks. The patients applied adapalene 0.1% gel to the whole face nightly throughout the treatment period. Treatment consisted of four sessions at 3-week intervals. The treatment parameters were wavelengths of 530 to 750 nm, at 7 to 9 J/cm2, in double 2.5-ms pulses, with a 10-ms delay, and a 10-×-48-mm spot size. The MAL incubation time was 30 minutes.

One quarter of the MAL-IPL group dropped out because of burning, stinging, and redness. Four weeks after treatment ended, inflammatory acne lesions had decreased by 53% in the MAL-IPL group, by 22% in the IPL-only group, and by 72% in the control group. At 12 weeks after treatment, inflammatory lesions had decreased 65% in the MAL-IPL group, 23% in the IPL-only group, and 88% in the control group. Only the control group experienced statistically significant decreases in inflammatory lesions from baseline at either time point.

Of the noninflammatory lesions, comedones decreased by 52% in the MAL-IPL sides, 16% in the IPL-only sides, and 14% in the control sides at 4 weeks. At 12 weeks, comedones had decreased by 38% in the MAL-IPL sides and 44% in the IPL-only sides and had increased by 15% in the control sides. The MAL-IPL sides had a significant decrease in comedones at both time points. Both the IPL-only and the MAL-IPL sides had a significant reduction of comedones compared with the control sides. Posttreatment hyperpigmentation developed in two patients on the MAL-IPL side and in one patient on the IPL side.


Neither topical photodynamic therapy nor IPL alone was effective for inflammatory acne in patients with Asian skin. The improvement in acne that did occur in these patients was probably caused by the nightly use of the topical retinoid during treatment, but the IPL-only treatment apparently reduced the retinoid’s benefits. The comedone reduction seen in recipients of the MAL-IPL combination resembles that produced by infrared lasers in another study covered in this issue (see JW Dermatology Apr 6 2007). Whether reducing comedones by these methods will, over time, lead to a reduction of inflammatory acne remains to be seen.


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