Isomorphic phenomenon of Koebner: facts and controversies.

Heinrich Koebner (1838-1904) presented in a meeting in 1872 and reported in 1877 the emergence of psoriatic lesions following trauma to healthy skin areas of patients with psoriasis. Since then, the Koebner phenomenon has been the subject of research, as it offers a unique opportunity in the investigation of the disease, especially in experimental studies, when this dermatosis may be observed in all its phases. Establishing the differences between Koebner, Wolf, Renbök, reverse Koebner, pseudo-Koebner phenomena, and pathergy is sometimes unclear. We review the various aspects of the Koebner phenomenon's clinical description and presentation, pathophysiology, histopathology, reverse phenomenon, therapeutic treatments, and prevention.