Dermatologists are doctors trained to treat issues with skin. They are trained in the science of dermatology, which is concerned with the diagnosis and treatment of diseases of the skin, hair and nails. Dermatologists typically provide treatment for skin cancer, warts, cosmetic filler injections, hair removal with laser, hair transplantation, laser therapy for birthmarks and skin disorders, tattoo removal, acne, sun damage, liposuction, radiation therapy, vitiligo surgery, and allergy testing.