A Feasibility Study of a Novel Low Level Light Therapy for Digital Ulcers in Systemic Sclerosis

Background: Locally acting, well-tolerated treatments for systemic sclerosis (SSc) digital ulcers (DUs) are needed. Objectives: Our primary aim was to investigate the safety, feasibility and tolerability of a novel low level light therapy (LTTT). A secondary aim was to tentatively assess efficacy. Methods: A custom-built device comprising infrared (850nm), red (660nm) and violet (405nm) LEDs was utilised. DUs were irradiated with 10J/cm2 twice weekly for three weeks, with follow-up at weeks 4&8. Any safety concerns were documented. Patient opinion on time to deliver, feasibility and pain visual analogue score (0-100,100 most severe) was collected. Patient and clinician DU global assessment VAS were documented. DUs were evaluated by laser Doppler perfusion imaging pre- and post-irradiation. Results: 14 DUs in 8 patients received a total of 46 light exposures, with no safety concerns. All patients considered LTTT ‘took just the right amount of time’ and was ‘feasible’, with a low associated mean pain VAS of 1.6 (SD 5.2). Patient and clinician global digital ulcer VAS improved during the study (mean change -7.1 and -5.2, respectively, both P= <0.001). DU perfusion significantly increased post-irradiation. Conclusions: LTTT for DUs is safe, feasible and well tolerated. There was an early tentative suggestion of treatment efficacy.