Dermatology is the branch of medicine focused on the diagnosis, treatment, and management of conditions affecting the skin, hair, and nails. As the body’s largest organ, the skin often provides clues about a person’s overall health, and dermatologists are specially trained medical doctors who can identify and address both cosmetic and medical issues. They treat over 3,000 different conditions, ranging from common problems like acne, eczema, and psoriasis to more serious or life-threatening diseases, such as skin cancer.