Topical
photodynamic therapy with 5-aminolevulinic
acid (ALA-
PDT) is a well-established treatment regimen for superficial epithelial skin tumours, but it is evident that inflammatory diseases of the skin and virus-induced lesions can also profit from
PDT. Depending on the light dose applied, either cytotoxic effects resulting in tumour destruction or immunomodulatory effects resulting in improvement of inflammatory conditions occur. Patients with
localized scleroderma that had been unresponsive to various treatments, including PUVA or bath-
PUVA therapy, respond very well to topical ALA-
PDT performed repeatedly. In contrast to
PUVA therapy, no carcinogenic potential is being discussed for
PDT. Also, HPV-induced skin lesions might provide a possible indication for topical ALA-
PDT. The rapidly proliferating cells in viral
acanthomas accumulate ALA-induced
protoporphyrin IX (
PPIX) selectively when compared to the surrounding non-infected cells. The efficacy of topical ALA-
PDT in the treatment of recalcitrant foot and hand
warts has been shown in a placebo-controlled, randomized, double-blind trial. Furthermore, case reports describe a good response of other virus-induced diseases, for example
condylomata acuminata and
epidermodysplasia verruciformis, to topical
PDT with ALA. However, controlled clinical trials are still needed to demonstrate more fully the effectiveness of
PDT for inflammatory
skin diseases.