Immunologic Profile of Chronically Photodamaged Skin

Chronically photodamaged skin is visually characterized by dryness, wrinkles, brown spots, leathery appearance, etc. This happens as a result of excessive exposure to UV light from the sun. While the sun's exposure leaves the skin's surface visibly changed, the skin's unseen immune system may also be permanently altered as a result of the exposure, making it more likely to develop a variety of skin cancers and infections. This study will examine the lasting changes in the immune system of the skin caused by UV exposure. Investigators will stimulate different aspects of the skin's immune system by giving an injection of Candida Albicans (CANDIN®) and histamine phosphate (HISTATROL®), topical applications of imiquimod 5% cream (ALDARA®) and performing a tape stripping procedure with adhesive tape. The use of Candida Albicans (CANDIN®), histamine phosphate (HISTATROL®), and tape stripping are common procedures in clinical settings to stimulate skin desired skin responses. Imiquimod 5% cream (ALDARA®) is an FDA-approved drug for the treatment of basal cell carcinomas, actinic keratoses and genital warts. Investigators will compare the reaction of the skin's immune system on a cellular level from skin normally exposed to the sun exposure to an area normally hidden from sun exposure.