| Haedersdal et al (2008) | 16 RCTs + 3 CTs (587 patients); optical treatments may improve inflammatory acne short-term with most consistent outcomes for PDT (up to 68% improvement; ALA/MAL + red light) |
| Hamilton et al (2009) | 25 trials (694 patients); mixed results—some short-term benefit with blue/red light and PDT; PDT benefits but side-effects and not superior to topical adapalene in some comparisons |
| Barbaric et al (2018) Cochrane | 71 RCTs (4,211 participants); overall limited/low-quality evidence; many modalities showed no clinically significant effects; adverse events variably reported |
| Zhang et al (2017) split-face RCT | n=12: 5% ALA-PDT with red light vs IPL—red light superior for lesion reduction; IPL better tolerated |
| Nicklas et al (2019) RCT | n=46: ALA-PDT vs doxycycline+adapalene—PDT had greater lesion reduction at 6 and 12 weeks; small sample limits conclusions |
| Darne et al (2011) 1,450-nm laser RCT | n=38 split-face: 1,450-nm laser showed no difference vs control in inflammatory lesion count or acne grade |
| Narurkar et al (2013) / Photopneumatic multi-center trial | n=41: photopneumatic + profusion topical agents—69% reduction in inflamed lesions at 3 months (physician assessment) |
| Zheng et al (2014) systematic review | 14 RCTs (n=492): various PDT protocols effective on inflammatory lesions; ALA+red light optimal; more RCTs needed |
| Lu et al (2020) meta-analysis of IPL | 8 RCTs (n=450): IPL less effective than controls for inflammatory lesions; inferior to PDT and PDL for some comparisons; common AEs erythema and pain |
| Posadzki & Car / Reviews on light therapies | Evidence for light therapies weak/inconclusive; red-light MAL-PDT only associated with small improvements not clearly clinically significant |
| Serini et al (2019) 5% ALA gel PDT | n=35 proof-of-concept: red-light PDT with 5% ALA thermos-setting gel produced ~70% GAG score reduction with good tolerability (medium-term) |
| Katz et al (2023) CellFX (Nano-Pulse Stimulation) | Feasibility n=17 (13 completed): CellFX-treated back areas showed 82% lesion reduction at 90 days; common erythema and hyperpigmentation; lidocaine required |
| Shi et al (2022) Tri-needle pretreatment + ALA-PDT RCT | n=48: tri-needle pretreatment improved effectiveness and reduced pain vs ALA-PDT alone but increased edema |
| Lee et al (2023) methylene blue nano-formulation | n=24: 5 weekly MB nano-formulation PDT showed marked lesion reduction and safety; preliminary evidence |
| Park et al (2020) gold nanoshell photothermal therapy (cases) | 2 refractory acne cases improved after 3 sessions with 3–4 month follow-up; preliminary case evidence |
| Artounian et al (2021) gold/silver nanoparticle systematic review | 16 original articles; nanoparticles promising adjuncts with phototherapy but clinical RCT evidence limited; further RCTs needed |
| Wang et al (2017) Chlorin e6-mediated PDT (preclinical) | In vitro and in vivo anti-inflammatory effects—down-regulated inflammatory markers and signaling pathways; supports feasibility |
| Choi et al (2018) ICG-based PDT | In vitro bactericidal effects; retrospective clinical analysis (n=21) showed decreased acne grade—preliminary findings needing validation |
| Modena et al (2020) Erbium lasers systematic review | 17 trials (453 patients): erbium glass/YAG lasers promising short-term with minimal AEs; long-term data limited |
| Erceg et al (2013) PDL review | PDL may be effective and safe for localized inflammatory acne (recommendation grade B) but most data not from RCTs |
| Wu et al (2021) red light meta-analysis | 13 RCTs (422 subjects): no significant difference vs traditional therapies for inflammatory or non-inflammatory lesions; mild AEs |
| Ash et al (2015) home-use blue LED RCT | n=41 (treatment n=26): blue LED reduced inflammatory lesions by ~50% vs +2.45% control at 12 weeks; small study, short follow-up |
| Cohen et al (2022) home-based devices review | 37 trials (19 RCTs): some home devices (LED-BL/RL) appear safe/effective but RCT evidence limited and heterogeneous |