Dermatology is the branch of medicine dealing with the skin, including its structure, functions and diseases. As a physician, Doctor Julian Bashir was versed in the dermatological prognosis and repair. In 2372, Miles O'Brien visited the Infirmary complaining about an enlarged sebaceous cyst growing on his neck. Dr. Bashir analyzed it, and told him not to worry about it because "dermatologically speaking, you're perfectly healthy." O'Brien continued to complain, calling it "a disgusting cyst on the back of my neck." He instructed Bashir to either take it off, or he would "paint a nose, eyes and mouth on it and pretend I've got two heads." Bashir agreed, and offered to get some paint, but O'Brien insisted on its removal. The doctor finally complied. (DS9: "Bar Association")