Isotopic response, Köbner phenomenon and Renbök phenomenon following herpes zoster.

Linear skin diseases may follow Blaschko's lines, Langer's relaxed skin tension lines or head zones (dermatomes), thus indicating an embryogenic, hematogenic or neuronal aspect in their pathogenesis. Köbner phenomenon describes the eruption of an inflammatory skin disease following mechanical alteration of the skin. Renbök phenomenon describes an area of non-involvement in an otherwise generalized skin disease. Wolf's isotopic response may be understood as a special subtype of Köbner phenomenon, in which one skin disease triggers a second one. Pathogenically unrelated skin diseases may follow a zosteriform distribution, if they are linked to a preceding herpes zoster by Köbner phenomenon, Renbök phenomenon or an isotopic response. We report three instructive patients diagnosed with Wegener's granulomatosis, cutaneous graft-versus-host disease and lichen planus, whose skin manifestations were following or sparing a zosteriform distribution pattern. Köbner phenomenon, Renbök phenomenon or Wolf's isotopic response may link pathogenically unrelated skin diseases to a zosteriform pattern, which may present diagnostic difficulties even for dermatologists.