A persistent, pruritic plaque on one shin has bothered a 75-year-old man for 5 years. Over-the-counter preparations have not resolved the lesion.
This excoriated plaque is lichen simplex chronicus, which is often referred to as “the itch that rashes.” This self-inflicted dermatosis is frequently triggered by a precipitating factor. To confirm the diagnosis, occlude the lesion so that the patient has no access to the area and examine it 1 or 2 weeks later. Invariably, significant healing will have occurred because the lesion was not rubbed or scratched. Occasionally, particularly in patients with long-standing disease, it is not possible to identify the inciting cause of the chronic itch/scratch cycle. However, it is reasonable to search for underlying chronic disease, such as venous insufficiency, myxedema, or xerosis. Tailor treatment to the inciting disorder. This patient had long-standing xerosis; a corticosteroid cream, and occlusive dressings, ameliorated the pruritic skin condition.