Adverse effects of topical photodynamic therapy

Background/purpose Topical photodynamic therapy (PDT) is increasingly used in dermatology, particularly for the treatment of superficial non-melanoma skin cancer and dysplasia. Treatment is generally considered to be well tolerated, although pain during PDT can be a limiting factor. This review explores the adverse effects of topical PDT. Methods A thorough search of the literature using Medline was undertaken and published data were evaluated and presented in conjunction with our own experience. Results Pain during PDT is the most commonly reported adverse effect and may prevent successful treatment delivery, although low-irradiance regimes and use of nerve blocks or cooling air can be used to reduce pain. Other acute and chronic adverse effects are reported but do not seem to be limiting factors in the use of topical PDT. To date, there is no convincing evidence for a carcinogenic effect of this treatment. Conclusion Topical PDT is associated with few significant adverse effects, although methods to optimize regimes and minimize pain are required to improve the acceptability of this therapy for patients.