Pigmentary Changes Following Photodynamic Therapy with 5-aminolevulinic Acid or Methyl Aminolevulinate Cream / 대한피부과학회지

ABSTRACT

BACKGROUND: Several side effects such as pain, erythema, and hyperpigmentation have been reported following photodynamic therapy (PDT). OBJECTIVE: We sought to compare the pigmentary changes induced by PDT with 5-aminolevulinic acid (ALA) and those induced by PDT with methyl aminolevulinate (MAL) in people with skin phototypes III-IV over a 6 month period. METHODS: In ten healthy volunteers, six skin areas on the upper arm of each subject were treated with (A) ALA 20% in base cream without irradiation, (A1) MAL 16.8% without irradiation, (B), (B1) control vehicles, (C) ALA 20% in base cream, and (C1) MAL 16.8%. Areas (B), (B1), (C), and (C1) were irradiated at four hours after photosensitizer or vehicle application. Irradiation was administered twice with a 1 week interval. The effects on the skin were assessed by visual and colorimetric evaluations. RESULTS: On (C) and (C1) areas, erythema and pigmentation were most pronounced at 30 minutes after the second irradiation. Erythema rapidly diminished but pigmentation persisted throughout the study. Erythema and pigmentation on (C)-treated areas were more prominent and prolonged than those on (C1)-treated areas. CONCLUSION: In subjects with skin phototypes III-IV, pigmentation tends to last for more than 6 months after PDT. The ALA-treated skin areas developed more severe and prolonged erythema and pigmentation than the MAL-treated skin areas.