Can tanning beds be used to treat psoriasis? Are they a safe alternative to phototherapy units?
There are differences in the purpose and delivery of light used in tanning salons. For one thing, most of the energy of a tanning bed is within the ultraviolet light A (UVA) wavelength spectrum of light. This spectrum doesn’t burn a person as easily or quickly as the lower wavelength UVB rays, so a person can stay in the tanning bed longer. UVB wavelengths are the most effective for treating psoriasis, so physicians use UVB to treat psoriasis. (For effectiveness and safety when using UVB in phototherapy, we limit the wavelengths of light to the most effective “narrow band” and try to eliminate the other unnecessary high-energy UVB light.)
Another consideration is the effect of UVA on the skin. These wavelengths help stimulate the manufacture of the skin pigment melanin to make the skin darker for protection, but the energy from UVA penetrates the skin more deeply than UVB rays. UVA more directly affects the collagen and elastic fibers of the skin than UVB and, over time, promotes damage such as wrinkled and aged skin.
There are testimonials—and some scientific evidence—that tanning beds seem to help psoriasis. Comparison trials in scientific settings have shown that small amounts of UVB contained in some of the tanning beds improve a person’s psoriasis. One of the options available at tanning salons is to get a quick tan, or “turbo tan,” by using certain devices. These devices have slightly higher percentage of UVB. These particular devices would have more effect on skin disease such as psoriasis, but a person is also getting very large doses of UVA, which will age the skin faster and promote an increased risk of melanoma because of the repetitive, high-energy light. It is dangerous, and increasing evidence seems to link early and frequent use of tanning beds with an increased risk of the most lethal skin cancer, melanoma.
Even though there has been continued scrutiny regarding narrow-band UVB and a possible increase in melanoma, so far no increase in risk for developing melanoma has been found with medical treatment using narrow-band UVB.