Skin reactions after photodynamic therapy are unaffected by 839 nm photobiomodulation therapy: A randomized, double‐blind, placebo‐controlled, clinical trial

Background and Objective Photodynamic therapy (PDT) is associated with erythema and edema. Photobiomodulation (PBM) therapy may stimulate the skin recovery process. We investigated the potential of PBM to reduce PDT-induced skin reactions. Study Design and Methods Healthy volunteers (n = 20) were randomized to receive left- or right side PBM (near-infrared 839/595 nm) or placebo-PBM (595 nm) on their buttocks. Corresponding test areas were exposed to standardized PDT reactions, using ablative fractional laser-assisted PDT (AFXL-PDT) with methyl-aminolevulinate (MAL) incubated for 30, 90, and 180 minutes before red-light illumination. Each buttock received PBM and placebo-PBM for five consecutive days, starting one day before PDT interventions. Follow-up visits were performed 4 and 11 days after PDT. Outcome measure included blinded, observer-assessed skin reactions, substantiated by objectively measured erythema and pigment percentages and skin temperatures. Results PDT interventions induced a standardized range of erythema and edema in all subjects. Skin reactions were clinically unaffected by PBM throughout the active treatment period and at all subsequent follow-up visits (PBM vs. placebo-PBM, P = 1.000). Clinical results were supported by similar erythema intensities and skin temperatures in PBM and placebo-PBM treated skin: median erythema 28.1% versus 30.3% (AFXL-PDT with 30 minutes MAL-incubation), 36.1% versus 35.2% (90 minutes MAL-incubation) and 39.4% versus 40.9% (180 minutes MAL-incubation) (Day 4, P > 0.05). No differences in clinical hyperpigmentation or pigment percentages were observed between corresponding test areas in any subject on the final 11-day follow-up. Conclusion Under the current study conditions, PDT-induced skin reactions were unaffected by PBM. Lasers Surg. Med. © 2017 Wiley Periodicals, Inc.