Arm of an African American female patient with lichen simplex chronicus (neurodermatitis). The patch of thick, leathery (lichenified) skin is caused by chronic itching and scratching. The condition is psychological in origin, with no underlying cause. The skin becomes irritated and itches, which provokes yet more scratching. Antihistamine or corticosteroid drugs may be given to relieve itching, and a dressing may be used to break the cycle of scratching.