ABSTRACT
Pruritus (itch sensation) was defined 350 years ago by a German physician, Samuel Hafenreffer, as an unpleasant sensation that elicits a desire or reflex to scratch. Itch/ pruritus is the most common symptom in skin diseases. At any given time, one of three people in the United States has a skin disease (Johnson 2004; Thorpe et al. 2004). Skin disease is listed as one of the top 15 groups of medical conditions in which prevalence and healthcare spending increased the most between 1987 and 2000 in the United States (Thorpe et al. 2004). The estimated cost of skin diseases, including direct medical cost and the economic burden on quality of life to the American public in a single year 2004, was approximately US$96 billion (Bickers et al. 2006). Actually, the significance of skin diseases is a worldwide issue. For example, 70% of people living in developing countries suffer from skin diseases at some points in their lives, but of these 3 billion, people in 127 countries do not have access to basic skin medications (Ersser and Penzer 2000).
