- The isomorphic phenomenon is the occurrence of the skin lesions in traumatized areas.
- This occurs in the following dermatoses: vitiligo, psoriasis, lichen planus, lichen nitidus, pityriasis rubra pilaris, and keratosis follicularis (Darier’s disease).
It was described by Dr Heinrich Koebner (1838-1904) in 1876, a German dermatologist who trained in Paris and Vienna:
- -he showed it a a patient with psoriasis
- -lesions occurred 5 and 6 years after the first plaque appeared occurring on traumatized areas: excoriations from riding, a horse bite, a tattoo, lymaphenitis-induced suppuration….the bite had exerted the greatest influence.
- -he demonstrated the fungal origin of sycosis barbae by inoculating human fungi in rabbits
- -he described epidermolysis bullosa simplex
For the anecdote, he was an enthusiast and didn’t hesitate auto-inoculate fungal infections !
Source of information:
-Crissey JT el al. Dermatology and Dermatologists (2002). Parthenon Publishing
Photo credit: picture of Heinrich Koebner from wikipedia