Gases around the earth cut off 98.7% of the sun’s ultraviolet radiation from piercing through our atmosphere. The 2.3% that penetrates may have bad effects when you get overly exposed, but in moderation, it actually has good effects on the skin.
UV radiation between 290 and 320 nm is referred to as ultraviolet-B (UVB). UVB radiation mostly affects human beings. UVB exposure generates the manufacture of vitamin D in the skin at a rate of up to 1,000 IUs per minute. Vitamin D has important roles in blood pressure, bone growth and maintenance of bone density, calcium metabolism, cell proliferation, immunity, insulin secretion, and the normal functioning of the nervous system.
UVB also fuels the production of new melanin that brings on ample increase in the dark-colored pigment of the skin. Additionally, UVB activates the cells to cause the expansion of the epidermis. As a result, UVB is accountable for the darkening and thickening of the outer skin layers, creating a defense mechanism against further UV damage.
UVB exposure can also restrain the clinical symptoms of multiple sclerosis due to vitamin D synthesis. In addition, UVB produces nitric oxide (NO) that can reduce blood pressure level and, in most cases, improve cardiovascular health.
UVB light is employed as a form of therapy for psoriasis, which is a long term skin problem that causes skin cells to grow too fast, causing thick, red, silvery, or white patches to appear on the skin. Studies have shown that when psoriasis, as well as vitiligo and eczema are exposed to UVB rays, there is a delay in the development of the skin cells, relieving the symptoms.
Before, UVA radiation was used together with psoralens in treating psoriasis; however, this combination produced a dramatic increase in skin cancer cases. These days, UVB radiation is used by itself because it is proven to be more effective. Also, a finer form of UVB has been developed, called narrowband, which contains only the wavelengths that are thought out to be most valuable in psoriasis treatment. In treating psoriasis, vitiligo, and eczema, UV light with a wavelength of 311 nm is most potent, which is why UVB lamps, like the Dermalight 80 handheld UV-B Phototherapy Lamp and DermaHealer handheld UV-B Phototherapy Lamp, make use of UV-B/311nm narrowband lamps.
UVB phototherapy has been proven effective in clearing the skin, and this commonly takes up to around 30 treatments over a period of several weeks. Treatment is mainly administered in hospitals using fully controlled courses supervised by a trained staff; although portable handheld UVB phototherapy lamps are now widely used in homes as well. Countless studies have demonstrated that narrowband UVB is far more superior to broadband UVB in clearing psoriasis, with shorter treatment times and reduced risk of sunburn-like side effects after treatment.