The Koebner Phenomenon in Its Relationship to Photosensitivity

Abstract

In 1872 Koebner described the phenomenon which bears his name, but a more detailed discussion by him is to be found four years later in the third volume of the Vierteljahresschrift für Dermatologie und Syphilis (1876). In refuting the theories of psoriasis as a dyscrasia or embolic skin reaction, he stated: "In my opinion there is present in the skin organ of the psoriatic a peculiar disposition, which, mostly hereditary but at times acquired, may remain latent for years. It may react to the most varying stimuli just in this pattern of inflammation of the skin . . . From this point of view there is an explanation for the sites of predilection of the first appearance of psoriasis and the but temporary results of local therapy !" It is important to note that Koebner includes in the varying stimuli which precipitate new lesions of latent psoriasis internal stimuli as