Ultraviolet rays are invisible, but are natural part of the sunlight that hits the earth all the time.  There are three kinds of UV rays — A, B and C — but UV-C (the shortest wavelength) never makes it through the atmosphere.

UV-A light isn’t as effective as UV-B rays at treating psoriasis.  This seems to be related to the fact that UV-B light is  harsher on the skin than UV-A light — UV-A tans the skin while UV-B burns it.

UV-B light has been proven to treat psoriasis all by itself, while UV-A light can treat psoriasis as long as it is coupled with a drug called “psoralen.”  This drug-sunlight combination has earned the nickname “PUVA.”  Psoralen can be administered orally or topically to enhance the skin’s sensitivity to light.  This doesn’t seem like such a good idea to me since sunlight can cause so many complications for the skin all by itself.   In any case, many people claim that PUVA works wonders for their skin.

Since UV-B rays have proven to treat psoriasis without help from any other drug, this kind of light has been singled out in UV emitting machines designed to treat psoriasis.

Keep in mind that UV rays have been proven to cause wrinkling (at best) and skin cancer (at worst) over extended periods of time.  So please exercise temperance along with any UV treatment (and you should consult with your doctor too of course).  Artificial UV light treatment in particular (as opposed to regular old sunlight treatment) should be administered under the watchful eye of a dermatologist since it’s easier to overdo it in the comfort of your own home.