UV radiation has multiple levels; for example, UVC rays are the most harmful to the skin and eyes, but the ozone layer blocks many of the rays. UVA rays play a considerable role in causing skin damage and aging. The wavelengths of UVA rays are long and are, therefore, less harmful than...
Occasionally, a large proportion of the scalp follicles begins to grow synchronously and so are in the same phase of the hair cycle. When this occurs and these hairs are shed at the conclusion of the telogen phase, there is extensive hair shedding. A variety of things seems to predispose to...