A dermatologist is a medical doctor specializing in treating conditions involving skin, hair, and nails. Board-certified dermatologists, such as the physicians practicing at DermSurgery Associates, have advanced knowledge, training, and skills acquired during a 3-year residency focused on dermatology and 10,000 hours of additional training. Some board-certified dermatologists specialize in specific areas, such as pediatric, surgical, or cosmetic dermatology.