This is a single site study to gain better understanding of the skin changes in allergic contact dermatitis (ACD), a skin condition caused by an allergic reaction to compounds in contact with the skin. Subjects will be patients who present to Banner University Medical Center (BUMC) dermatology clinic for routine patch testing to identify potential compound that may be causing their pre-exiting rash. Any positive skin reactions found on patch testing reading examination will be photographed using a multimodal digital camera (MDC) that can capture high resolution skin surface images and information beneath the surface.