The isomorphic response of Koebner can be observed not only in psoriasis, but 
also in other diseases, such as lichen planus and some systemic diseases 
including LE (lupus erythematosus) or sarcoidosis. Several clinical findings in 
LE skin were presented and discussed in this review. The mutually-interactive-, 
negative-, and internal-Koebner phenomena were introduced and discussed with 
some speculative views. Many forms of environmental stress on the skin were 
reported as provocating factors of the Koebner phenomenon, including trauma, 
scratching, UV-exposure, and various types of dermatitis. Clinical observations 
of the nature, localization, and movement of lesions should be carefully made. 
The pathophysiology of the Koebner phenomenon may be classified into two steps. 
A first non-specific inflammatory step and a second disease-specific step. The 
inflammatory products released from the first step would be targeted in the 
second step. In the first step, there could be many substances including 
cytokines, stress proteins, adhesion molecules, or autoantigens translocated 
from intra-cellular areas. In the second step after latent periods, there may be 
disease-specific reactions, including ones by T-cells, B-cells, autoantibodies, 
and immune deposits, under the restriction of genetic backgrounds. The Koebner 
phenomenon may prove useful in understanding the pathophysiology of diseases of 
unknown origin.