Lichen planus (LP) can be very pruritic. The classic signs are scaling and purple-to-brown polygonal papules on the wrists, forearms, and legs (Fig. 22-1). The papules are flat on top. A white, shiny, lacy pattern, called Wickham’s striae, can sometimes be seen on the surface of the papules after application of a drop of oil. A hand lens may be needed to detect this. Approximately two thirds of patients with LP have reticular, white patches or plaques on the buccal mucosa (Fig. 22-2). The head of the penis may also be affected. Hypertrophic LP is a variant, in which thick, large plaques appear on the distal extremities, particularly on the shins. LP of the nails may cause obliteration of the nail fold (pterygium), longitudinal ridging, and pitting.