Chapter 18 Topical sensitization—non-oncologic indications—HPV-infections

Abstract

Although malignant and premalignant lesions are still the major targets, PDT may be used for eradicating non malignant growths such as human papillomavirus (HPV)-induced acanthomas of the skin. 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 sought. HPV-induced skin lesions might provide a possible indication for topical ALA-PDT. The rapidly proliferating cells in viral acanthomas accumulate ALA-induced PPIX selectively when compared to the surrounding non-infected cells 25. , 26. . Also, more recently ALA-PDT has been shown to have antiviral properties [13] and may be a new approach to destroy cells altered by virus infection by the interaction of absorbed light and the activated phototoxic agent. This chapter shall provide an overview including the different features of HPV-induced skin lesions, epidemiology, recurrence rates and treatment options as well as a brief review comprising the rationale of PDT in treatment of virus acanthomas as well as results of first clinical studies.