Gel nails are a common artificial nail option. Ultraviolet (UV) nail lamps are commonly used to cure gel nails. Ultraviolet A radiation is a known mutagen that penetrates into the nail bed. Although previously reported, the role of UV nail lamps in the carcinogenesis of both keratinocyte carcinoma and melanoma remains controversial. Herein, we report a patient taking the photosensitizing agent hydrochlorothiazide who developed numerous squamous cell carcinomas on the dorsal hands and feet with a 10-year history of UV nail light exposure every 2-3 weeks.