This updated fourth edition provides updated information on medical conditions that affect the skin, hair, and nails. It describes the basics of healthy skin and skin care; explains prevention, warning signs, and treatment options for skin cancer; and spells out the risks of tanning. Acne is discussed in depth, and common conditions such as allergic rashes, cold sores, and minor skin injuries are also covered. Information to help teens make healthy choices regarding cosmetics, piercing, and tattoos is also included.