Dermatologists are board-certified medical doctors who are trained in the diagnosis, treatment and prevention of disorders related to the skin, nails and hair. A dermatologist is the expert you need whenever you have concerns about conditions like acne, skin cancer, rashes, wrinkles, warts, psoriasis, eczema, hair loss and nail fungus. At SIU Medicine, we advise most people to see a dermatologist once a year, although some individuals may need more frequent visits depending on their health history and personal risk factors. Seeing a dermatologist regularly—even if you don't currently have any