Lichen planus is a benign growth caused by HPV infection of the skin and mucous membranes. It occurs on the face, back of the hands and forearms of adolescents. The typical lesions are flat elevated papules, round or oval, smooth, hard, normal or light brown in color, appearing suddenly, in large numbers and densely packed. The course of the disease is chronic, and sometimes it can subside on its own, but a few patients can be stubborn, perennial, or even outbreak state. The physical and mental impact on patients is high.
Traditional treatment methods including antiviral drugs, immunomodulatory drugs, Chinese herbal medicine, topical drugs and physical therapy are difficult to achieve satisfactory treatment results. In addition, the topical photosensitizer ALA does not remain in the treated tissues for more than 24 hours, so it will not lead to long-term accumulation of the drug in the tissues and increase phototoxic reactions to multiple treatments. Therefore, photodynamic therapy can be a better treatment for persistent eruptive warts.