Photodynamic therapy for keloids and hypertrophic scars: a review

Keloid is a poorly understood disease that is unique to humans. Hypertrophic scars are similar to keloids and may transform into keloids over time. The standard treatments for these scars are limited by inconsistent efficacy and long treatment/follow-up times. Therefore, a new treatment that is effective for all abnormal scar cases is needed. One option may be photodynamic therapy (PDT). This review assesses the current evidence regarding the safety and efficacy of PDT for keloids and hypertrophic scars.

PubMed, Medline and Web of Science were searched from 1900 onwards for the following terms: 'keloid and photodynamic therapy (PDT)'; 'hypertrophic scar and photodynamic therapy (PDT)'; and 'scar and photodynamic therapy (PDT)'. Articles were included if they reported using topical PDT to treat keloids or hypertrophic scars, the patient(s) had one or more keloids and/or hypertrophic scars, and the effect of PDT on these abnormal scars was described.

In total, 538 articles were identified. Thirteen fulfilled all inclusion criteria. Eight were laboratory studies on keloid/hypertrophic scar explants, fibroblasts or tissue-engineered skin models and five were clinical studies/case reports. The clinical results of PDT on keloids and hypertrophic scars are encouraging.

PDT appears to play a promising role in keloid and hypertrophic scar therapy but additional clinical studies, particularly randomised clinical trials, are needed.