Is phototherapy really good at controlling psoriasis?

Psoriasis Light Rx. Psoriasis is a autoimmune disorder that causes the build up of skin cells, with redness and scale. It was discovered along time ago that exposure to sun light helps psoriasis.. Other, man made light sources are also used, . There are several kinds, using uva, or uvb, or narrow band uvb. Chemicals, like coal tar, are sometimes used with the light. The light can damage the skin and cause cancers.
Yes. But not always. The psoriasis can respond well to the light or phototherapy. We see this naturally because psoriasis does better in the summer when we have more sunshine. Unfortunately it does not always eliminate the psoriasis and then additional therapy may be necessary.