Laser Hair Removal

Laser hair removal is one of the most common non-surgical procedures performed in the United States. Excessive, unwanted hair can be seen in all ages, ethnicities and skin types and lasers can help provide a permanent reduction in hair growth. Professional and home-based laser and light systems are both currently available, with professional systems including the 694 nm ruby laser, 755 nm Alexandrite laser, the 800 nm diode laser, the long-pulsed 1,064 nm Neodymium doped: yttrium aluminum garnet (Nd:YAG) laser, intense pulsed light (IPL), and radiofrequency. While generally safe, side effects from laser hair removal are possible and should only be used by trained medical professionals after performing a thorough history and physical examination. This chapter will provide a succinct approach to laser hair removal, including but not limited to available modalities, patient selection, reported side effects and management of care

Gerontobiology of the Hair Follicle

NoThe word ¿gerontology¿ is familiar to most of us as a term that captures the study of the social, psychological, and biological aspects of aging. However, its derivative ¿gerontobiology¿ as applied to the hair follicle is more concerned with the latter aspect ¿ the biology of aging in the hair follicle mini-organ. As with any complex multicellular tissue system, the hair follicle is prone to broadly similar underlying processes that determine the functional longevity of organs and tissues. No matter how complex the tissue system is, it will contain cells that eventually lose functionality, reproductive potential and will ultimately die. The hair follicle is somewhat unusual among mammalian tissues in that it is a veritable histologic mélange of multiple cell types (e.g., epithelial, mesenchymal and neuro-ectodermal) that function contemporaneously in all stages of their life histories e.g., stem cells, transit-amplifying cells, and terminally differentiating cells. Some of these interactive cell systems appear to be nonessential for overall hair follicle survival (e.g., melanocytes). However, strikingly graying hair follicles may grow even more vigorously than their pigmented predecessors. Moreover, the hair follicle is unique in the adult mammal in that it follows a tightly regulated script of multiple lifelong cycles of cellular birth, proliferation, differentiation, and death. Powerful evolutionary selection ensures that the hair follicle is, in the main, hardwired against significant aging-related loss of function, even after 12 or more decades of life ¿ although some would argue with this view, if only on purely cosmetic grounds. Processes underlying aging in general, e.g., oxidative damage, telomere shortening, age-relating deficiencies related to nuclear/mitochondrial DNA damage and repair as well as age-related reductions in the cells¿ energy supply, will all impact on whether some follicular cell subpopulations will enter cellular senescence. This chapter will focus on how gerontobiology of the hair follicle may impact on certain aspects of hair fiber phenotype