There are two types of ultraviolet light which occur naturally in sunlight and are used therapeutically: UVA and UVB. These have proved helpful in treating a variety of skin conditions. Some of which are: psoriasis, eczema/dermatitis, pruritis, mycosis fungoides, vitiligo, lichen planus, granuloma annulare, alopecia areata and polymorphous light eruption.
The ultraviolet light works in a variety of ways, according to the condition for which it is being used. It can: suppress an overproduction of skin cells, stimulate skin pigment productions, and affect the immune system which can aid in healing the skin. Phototherapy is not a cure but it is a means of clearing and controlling certain skin conditions and often decreasing or suspending the need for cortisone use.
A phototherapy consult needs to be scheduled in order for the doctor to determine whether these treatments are appropriate and which would work best. Patients generally begin therapy by coming three times per week. As their skin improves, the frequency is tapered. There are certain skin problems for which an extended maintenance regimen keeps the condition in remission.