Photodynamic therapy with 20% aminolevulinic acid for the treatment of recalcitrant viral warts in an Asian population

Abstract

Background: Topical photodynamic therapy (PDT) is based on the principle of targeted tissue destruction using selective photosensitization via a topical porphyrin precursor, followed by light exposure. It is well established for the treatment of actinic keratoses and superficial nonmelanoma skin cancers. Some studies have reported good efficacy when using PDT to treat viral warts in the Western population.

Methods: We carried out a prospective, single-arm, phase II study of 5-aminolevulinic acid (5-ALA)-PDT in the treatment of recalcitrant viral warts in an Asian population. Recalcitrant viral warts were surgically pared, and then treated with 20% 5-ALA cream (Medac, Hamburg, Germany) under occlusion for 4 hours before irradiation with a red light source (Waldmann PDT1200; wavelength, 590-700 nm) at an irradiance of 50 mW/cm(2) and a total dose of 50 J/cm(2). PDT was repeated fortnightly for a maximum of four times.

Results: Twelve adult Asian patients were enrolled into the study (10 males, two females). The mean age of the patients was 32.8 years (range, 18-70 years). They had skin phototypes III-IV. Nine patients had plantar warts and three patients had hand warts (two had warts on the fingers, one had a wart on the palm). Five patients (42%) showed complete disappearance of their warts, one patient (8%) showed partial clearance (greater than 50% decrease in the wart area), five patients (42%) had stable disease (less than 50% decrease in the wart area), and one (8%) showed progressive disease (increase in the wart area). Adverse effects included mild to moderate pain and erythema, which lasted no longer than 48 hours and was well tolerated by all patients. None of the patients withdrew from the study because of side-effects.

Conclusion: 5-ALA-PDT, given its noninvasiveness, minimal adverse effects, and good cosmetic results, is a promising alternative treatment for recalcitrant viral warts. Further studies with a larger cohort of patients would be of value.