History: A young girl presented with a unilateral asymptomatic linear slightly erythematous plaque covered with white silvery scales with some transverse fissures. The lesion extended from the base of the big toe to the middle of the leg of many months duration. Linear configuration in psoriasis may rarely occur spontaneously or more commonly as an isomorphic (Koebner's) phenomenon. Histological features of skin biopsy were more in favor of psoriasis than lichen striatus.