Dermatologic disease, although seldom life threatening, can be extremely disfiguring and interfere with the quality of life. In addition, as opposed to other organs, just the aging of skin and its adnexal structure the hair follicle can result in cosmetic concerns that affect most of us. The articles in this dermatology Review Series demonstrate recent progress in understanding the cell biology and molecular pathophysiology of the epidermis and hair follicles, which harbor keratinocyte and melanocyte stem cells. They reveal a dynamic relationship between research and clinical care: knowledge of dermatologic disease has facilitated the understanding of the biology of the epidermis and, in turn, progress in basic science has informed our understanding of disease. This type of synergy is a profound strength of clinical research of the type that the JCI is dedicated to publishing.
IntroductionThe Reviews in this series highlight the progress in understanding several dermatologic diseases that are particularly important because they are common and/or disfiguring. Kubo et al. (1) highlight recent major progress in understanding the pathophysiology of atopic dermatitis (Figure 1), a disease both very common (estimates are 10%-20% prevalence in children; ref.2) and potentially severe and difficult to deal with for both patients and parents. Myung and Ito (3) discuss recent progress in understanding the bulge of the hair follicle and its importance in harboring both keratinocyte and melanocyte stem cells. Understanding the cell biology of the bulge is important for dissecting the pathophysiology of skin cancer-like basal cell carcinoma (BCC) as well as the potentially disfiguring disease vitiligo (Figure 2). In addition, the melanocyte stem cell contributes to hair pigment. Insights into this stem cell may help us understand the physiologic process of the graying of hair with age. Normal graying of hair, although not a disease, is of great concern to millions of people, probably because pigment in hair is an indication of youth (Figure 3). Finally, Kasper et al. (4) and Ratushny et al. (5) discuss new aspects of the pathophysiology of skin cancers. Not only are cancers of the skin some of the most common cancers in humans, but they can be terribly disfiguring if left untreated (Figure 4).