Dermatology is the branch of medicine dealing with the skin, nails, hair and its diseases. It is a specialty with both medical and surgical aspects. A dermatologist is a physician who specializes in the treatment of skin conditions and diseases. Dermatologists are certified by the American Board of Dermatology after extensive education and medical residency. They treat everything from minor skin rashes, like hives, to chronic skin diseases, such as eczema or psoriasis. Dermatologists are good diagnosticians and can distinguish between conditions that share similar symptoms. Today many dermatologists are also well versed in cosmetic dermatology procedures to help improve the appearance of skin as we age.