Dermatologists are physicians devoted to the medical and surgical treatment of diseases pertaining to the skin, hair and nails. In order to be designated a specialist in dermatology, the doctor must complete three years in a certified residency program, after completing an internship following four years of medical school. Upon completion of their residency, a dermatologist must take a certifying board exam given by the American Board of Dermatology. By passing this test, a dermatologist is able to say that he is a Diplomate of the American Board of Dermatology, or commonly designated a “board certified dermatologist”.