Medical Dermatology Dermatology is a specialty field of medicine. A dermatologist completes medical school and at least five years of training after that. They must then pass extensive written, oral and practical examiniations to become board certified in their specialty. The skin is the largest organ in the body and dermatologists look after skin, hair and nails, so you can see why their study is so extensive. Dermatologists also work in conjunction with a host of other specialists to treat systemic conditions that affect the skin.