Skin disorders that improve by exposure to sunlight

Abstract

T he sun has been an omnipotent, almighty diety from the beginnings of human history throughout the world. The sun was much more indispensable to the ancient people than to us because of its warmth (infrared radiation) and its light (visible radiation). It was also needed to produce crops. The ancient people prayed to the sun god for everything, and disease was not an exception; therefore, phototherapy began as sun worship. As time passed, beneficial effects of sunbathing on selected skin diseases were recognized from long term-experiences. It is said that the Egyptian ruler, Amenhotep IV (14 century BCE), already knew the efficacy of sun rays for the prevention of rickets. Phototherapy is also called heliotherapy, which is named after Helios, who was the sun god of the ancient Greeks. Modern phototherapy and photochemotherapy developed only as based on 20th-century science. Accordingly, phototherapy developed from sun worship, through experience, and now is an accepted scientific treatment as a result of clinical studies and advances in photophysics, photochemistry, and photobiology. At the present time, phototherapy is one of the most im-, portant therapeutic modalities in dermatology.