Photodynamic Therapy for Human Papilloma Virus-Related Diseases in Dermatology

Summary Although malignant and premalignant lesions are still the major targets, photodynamic therapy (PDT) may be used for eradicating non-malignant conditions such as human papillomavirus (HPV)-induced acanthomas of the skin and adjacent mucous membranes. HPV-induced skin lesions are very common and can present as foot and hand warts, planar warts and genital warts. Histologically these lesions display an acanthotic epidermis in a hyperproliferative state. The clinical course is characterized by high recurrence rates despite of surgical removal or application of cytotoxic agents. The variety of clinical treatment regimens demonstrates that no single treatment modality to date has been fully satisfactory and additional methods should be taken into consideration. HPV-induced skin lesions might provide a possible indication for topical PDT utilizing 5-aminolevulinic acid (ALA). The rapidly proliferating cells in viral acanthomas accumulate ALA-induced protoporphyrin IX selectively when compared to the surrounding non-infected cells. Also, more recently ALA-PDT has been shown to have antiviral properties and may be a new approach to destroy cells altered by virus infection by the interaction of absorbed light and the photosensitizer.