The modern paradigm of phototherapy.

The recognition of medical benefits obtained with suberythemogenic doses of natural sunlight extends back centuries. Modern medical application of phototherapy has been in place for over 100 years. It is the nature of scientific discovery to depend upon the use of new investigational methods or new devices to gain a better understanding of the mechanisms involved with the observed effects. Advancements in the field of photobiology and in the development of delivery systems for light therapy, such as narrow band UVB and laser, has given us additional insight into why and how phototherapy works in regards to treatment of skin disease and conditions of the skin. This discussion will primarily focus on ultraviolet light, photochemotherapy and a brief mention of photodynamic therapy.