The skin plays a major role in maintaining the body’s homeostasis. The well-trained primary care provider, however, must be able to recognize the more subtle changes of the skin and distinguish between life-threatening diseases such as malignant melanoma and less serious, common skin conditions. This chapter starts with the basic vocabulary necessary to describe and diagnose dermatologic conditions. Common skin diseases are then described in detail, including diagnosis and management. Varying social and environmental factors also influence both the occurrence and the detection of skin disease. The diagnosis and treatment of skin disease depend on the health care provider’s familiarity with dermatology terms. Acne is a multifactorial disease that involves the formation of the comedone and principal factors in its pathogenesis: distension of follicles by a keratin plug, increased sebum production, abnormal keratinization of the follicular epithelium, proliferation of Propionibacterium acnes, and increase in inflammatory mediators.