Epidermal Nevus Represent a Segmental

psoriasis/LP represents a further segmental type 1/type 2 mosaic of psoriasis which, if a (verrucous) epidermal nevus exists, shows a high affi nity of occurrence in close context to such a nevus. Heritability is thought to be pos-sible. Copyright © 2006 S. Karger AG, Basel Psoriasis vulgaris, today recognized to be the most prevalent autoimmune disease in man [1] , is thought to be caused by genetic and environmental factors. Most molecular genetic examinations propose a polygenic ori-gin [2]. Type I psoriasis is defi ned by early onset, herita-bility, high association with human leukocyte antigen (HLA) and a strong tendency to become generalized, while type II psoriasis is characterized by later onset, weak HLA association and a sporadic appearance [3]. Nevoid/linear psoriasis (LP) without further signs of pso-riasis is rarely reported [4–6]. Three reports of LP exist occurring in a patient with psoriasis vulgaris [7–9]. Infl ammatory linear verrucous epidermal nevus (ILVEN), described in 1971 by Kaidbey and Kurban [10] and Altman and Mehregan [11] , always follows the lines of Blaschko. ILVEN, similar to other nevi, is proposed to refl ect genetic mosaicism [12]. Cases where there are no clear-cut detectable differences between ILVEN and a possible LP make it diffi cult to characterize ILVEN as